Steptoe

Didn't realise the 16mm was the incoming feed, I'm in agreement, I don't think its big enough when you take into account VD, With an 80a ocpd, I think you are going to have to go 25mm, but do the calcs, btw @JSHarris the collet rings are often used by some manufacturers where a gland has multiple cable sizes, so at the larger end if the scale they are often redundant But very gland dependant, you can tell by the inner seating design.

Its not a problem with the emf, its more an issue with the cat5/6 not being rated at 230v, So really needs its own duct, If you are running 2 cat6 with bends it might be a lot easier using 25mm conduit, and sweeping bends, cat6 doesn't like elbows. Why the separate cpc,? The armour of 16mm is plenty big enough, or, if you must, use 3core, but there's really no need, unless there is some other reason,

Lightning conductors, There is a reason these guys pay insurance premiums in 5 and 6 figure sums, Not a diy job, I done some subby labouring for some guys doing a hospital once, everything has specific distances from everything else. Tapes need to be certain distance apart, and from other stuff, ground mats have to be in certain places according to the services. I personally wouldn't even consider touching it myself. ps, TN-S on an overhead,? Is that a peculiar English thing,?

The biggest problem with having a Genny for back up is how do you separate the earthing systems , and how are you going to earth the Genny to the house, you can't use the DNO earth with a Genny, 2 totally different system types. Needs very careful consideration.

I can vouch for ballykelly Joinery too, I could get you numbers for a couple of bespoke small joinery companies too if you want, the company my BiL works for that make bespoke kitchens work fairly closely with some fit-out joiners.

Denmans have them, I got one 2 weeks ago on a next day from another branch as my local had none in stock. No idea on price, would need to check the chit.

Do not use flexible duct, that's just pure and simply poor design. If a fan is designed for 4" duct and you want to use flexible you need to use 16", and its still not as efficient due to 'swirl' in the pipe. And, each 90degree bend is another 1/4 size as well, try and use 2 x 45s instead. As above, inline centrifigual or bifuctecated is the answer, but bifuctual is probably massive overkill for a domestic, even a large domestic. A good 4" centrifugal will work with well over 5m of 4" (solid) duct, but tbh, at that length a 6" is going to be way more efficient.

Have you tried a gigabag,? They only guess at you tethering due to your data usage, they can't actually tell, Get a Draytek, or some other decent router, Mine is only a basic one and it logs usage , total usage, and individual from each IP or Mac connected. As above, Any decent router can log usage go TT business, had my fault fixed within 3 days and previous months bill credited for inconvenience

You may have to remove before you purge, I'm not massively into exactly how Raspbian works, but some *nix flavours require it this way, Also , apt-get has mostly been changed to just apt now, but again, I'm not sure if this applies to Raspbian either, Although I do have some issues with some code I've transferred from Wheezy to Jessie , I'm not convinced Jessie isn't without its problems tbh. I'm reverting that one back to Jessie as the rest of my Pi's are running fine on Wheezy, but the one on Jessie is giving problems.

OK, I've noticed a lot of times people referring to the high cost of antifreeze in GSHP, does nobody run glycol in their ASHPs,? Makes for a way more efficient system, and its actually extremely cheap for the small amount you need, generally sub £100 for a typical system, and a heck of a lot cheaper than 'water wetter' , albeit just not quite as efficient as WW. That is assuming they are proper ASHP and not remanufactured AC units that a lot of places sell.

I've seen evidence of the leeching effect, As long as the substance actually states its OK then I don't see any issue, but I wouldn't just use any random sealant. I've seen newish T&E in a loft almost completely stripped by polystyrene bead type insulation, In general I stick to using a standard type 'compound' , But if @Onoff reckons its still OK, then I'm sure it is, And I'm sure @ProDave knows of more specific types for better properties at insulation etc most likely. It was just a general warning that not just any old expanding foam/silicon should be used in contact with PVC cables.

do NOT foam and silicon the cables, unless you are absolutely certain it will have no detrimental effect on the cable, there is proper stuff to use, compound, there may be a proper non trade name for it, perhaps @ProDave or @Onoff will know it, Most silicons and foams will 'eat' into the cable

That's not as tidy as your last pic suggested,

Oh, if your really lucky it'll be the C70, the fastest bestest one of them all, And, indestructible, I'll pick it up in the morning shall I ?

I know a guy that will design you a 2 stroke exhaust from your cylinder capacity , port timings, and where in the revs you want the power and he will send you either a kit or the drawings made out just like that. Arcs, widths, lengths, and you just weld it together in situ to get the clearances you need,.

I'd seriously consider getting myself one of them for work at that price, ps, get yourself some proper cutting compound,

That's cheap @Construction Channel My mates was a little further into almost 5 figures,!!!! And a tad bigger, But , he does do stuff slighter bigger than you'd find in the average house, I never asked him if he had a smaller one, it just happened to be the one he had in his van the day I saw it and blagged it off him for a job.

Have you seen the price of those things!!!!!!! My mate has one, usually used to drill them before they get erected. It wouldn't be the easiest thing to be lugging about and throwing onto steels above your head sideways, Oh well, just be an extra on the customers bill I suppose

What with,?

For my tuppence worth, if you are unwilling to spend upwards of £5k + the designers cost , for 'normal' not automated lighting, don't go for a lighting designer. How many of you have got interior designers in to design your furniture for you,? May also be a good idea to note their disclaimers,,,,,, Bit like surveyors, they take absolutely no responsibility if it turns out shit. The only time I have ever found their designs are any use have been in commercial/industrial situations where they will warranty what they design will meet statutory requirements. And that's a totally different sort of designer, a domestic lighting designer is merely charging you a lot of money to tell you where they would put the lights if it was their house, imo.

Rather you than me,,,, Two methods I can suggest to terminate 4mm to a normal plug, 1st is to use a 16a plug, then a short patch lead of 13a plug to 16a socket in 2.5mm 2nd is simply to use one of the proprietary inline IP rated connection tubes/tunnel thingies (I think that's the technical term) I prefer the first tbh, all my 'made' extension leads are done with 16a plugs/sockets and I have short changeover patch leads for each end, some of my stuff needs 16a, and some of my outside sockets are 16a, as is my house inlet (for Genny) and van inlet.

The only thing I may suggest about @TerryE suggestion is, Don't buy a long extension lead, they are usually only 1.5mm , buy a 100m drum of 2.5 (or 4mm) artic flex and make your own, Allows a bit more give on the volt drop, obviously will need jointed down to 2.5 at the plug end. You could even get yellow so it's more visible, The blue for 230 and yellow for 110 isn't actually a fact btw, just a common usage thing. I once had a H&S guy come storming into a house I was working in on a large site with site foreman and contracts manager in tow shouting and demanding I get threw off immediately as I was using 240 (pre harmonisation) tools. He had seen the blue lead going through a window, He soon quietened down and shuffled off again when he saw 110 plugs and sockets on everything. I'd had some blue artic in the van so used it to make an extra lead from.

If the back boxes are metal, fixed to the rear of the 50mm service void, how has @JSHarris enclosed the cables between the back box and the accessory,? Even with a massive 47mm back box its still not enclosed,??? I'm just not understanding anybif the logic here whatsoever , obviously I'm missing something very simple, like not seeing the wood for the trees kinda thing. @Barney12 I have seen them surface mounted on the underside of wall cupboards, but that requires a rather large pelmet,,, ,,,,,,

I don't understand why the sockets weren't put behind/inside the unit in the first place with just a switch outside, That would have looked terrible with trailing flexes through the side of the unit. Then one of the sockets could have been changed to an outlet plate as @Onoff suggests. And I think this is another one of those occasions where proper terminology needs to be used, as it does appear they were indeed radials and not spurs.

I've ran out of likes, But @TerryE solution is one way to consider, Cheap and cheerful, KISS as they say,