ProDave

I had similar with car insurance. When I built the garage at our house I declared to my insurance on renewal the car was parked in a garage. THEN they told me the reduction in the premium was £0. I then asked what if one night I left it on the drive and it was nicked. Sorry not covered. Needless to say it is declared to the insurance now as stored on the driveway overnight. Madness.

This is not "advice" but mine (different make design) came to a dead stop against a flimsy plastic pip and maxed out at barely 60 degrees. Turning it a "little" harder the pip broke off. I then turned it further a little each day noting now hot the cylinder got before it cut off. I stopped at 75 degrees. If you try anything similar, entirely at your own decision and risk.

The quality of work is going down hill.

I think the more important question might be what is above the ceiling? What is making that one of a set of identical lamp holders get hotter than the rest? Is something blocking the ventilation holes? Is there insulation there? Is there a hot pipe running through that section of ceiling meaning it is a much warmer space? etc etc.

Post some pictures including the areas of concern.

Like when I energise a new electrical install I say "time for the smoke test"

I used flexible I think it was 70mm twin wall. If it is bought as conduit, the inner wall is a lot smoother than the outer corrugated wall, and it comes with a draw cord installed already, but that is usually just a bit of fishing line, so first use that to draw a decent bit of rope through before burying it.

I would go for outline planning, that is what most buyers of a plot would expect. You can include as much or as little detail as you want, but the drawings can be a lot less detailed than full planning so quite possible to DIY if you want to. From the fees point of view a normal planning application looks far better value than any pre app advice which we know from this forum is likely to be inaccurate an non binding any way, i.e. a waste of time and money.

There is your answer. the conduit is probably crushed by a stone somewhere and sadly useless. For anyone reading, only use a much larger smooth sided rigid conduit. 50mm absolute minimum.

Henley blocks and your bank of switch fuses need to be withing 3 metres of the suppliers meter. Simple.

Often the first sign of trouble?

Leave them alone. Some future electrician will thank you when he can thread a cable through the existing hole rather than drill a new one.

A "Bulb" is something you plant in earth and it grows into a plant.

Don't fit UFH in this situation. Your overlay boards will not have anything like enough insulation to sit directly on an uninsulated floor. If you do proceed expect a lot of your heat to go down and very poor performance.

Put all your "plant" stuff along the back wall of the garage, and I bet you will still fit 2 cars in there.

What restricts you to 40mm? What is the bottom of that 40mm? 25mm battens UFH pipes between pug mix and 20mm engineered wooden floor is what we have, only 5mm "too thick" for you. What insulation and floor build up below your 40mm starting point?

And unless the run to the sub boards is long, once fused down 16mm is plenty.

I would go straight from meter to henley blocks then feed each SWA with a switch fuse.

Henley blocks don't provide isolation and over current protection of the submains, so your electrician is correct.

Here in the Eastern Highlands, -10 is not uncommon so I sized my ASHP for that. Heat loss at -10 and +20 inside is just over 2kW so at -15 it would still be under 3kW so a 5kW ASHP does the job nicely. I think -18 is the coldest night so far but that is not a sustained cold. So your heat losses are coming out about twice mine for a similar sized house. Defrosting is not usually an issue well below 0, there simply is no moisture in the cold air. Defrosting is mostly an issue around and a few degrees above 0.

There is no hard or fast rule. Try rigging it up on a bench before comitting just to ensure there are no problems. By the way I never use low voltage downlights, that is just one more thing to fail. I much prefer GU10 mains downlight with LED lamps in them. I walk a mile from any that do not have replaceable lamps, because you can almost guarantee in a few years when a sealed one fails you can't buy identical replacements.

My money is two 2 port valves, one for radiators and one for UFH, and the feedback microswitch in the UFH one has failed. Are there any 2 port motorised valves anywhere? Of course this is basic stuff and it is a poor show that plumbers and electricians have failed to find the fault. I hope you have not paid them?

Ignoring the tree you might have a bigger problem. Is this foul drainage with a treatment plant or rainwater? Check your local building regs. Here in Scotland a drainage field must be 10 metres away from a road. That is what scuppered us, but drainage to the burn came to our rescue. What is behind you? A field? Can you get permission to drain there?

Also poor design compared to UK 13A plug. Where are you to have this in use?

It should not need to get warm enough to warm your feet. Does it put enough heat into the rooms to get them to the set temperature?