ProDave

Thanks for letting us know the result. IMHO those are not the best valves, not the ones I would choose but I doubt you chose them either. My view of that make is tainted by a job I had where the head had failed beyond repair, so bought a new head, only to find at some point they had changed the design of the valve body and the new head would not fit the old body even though they looked identical.

Do NOT have an extract in the pantry. That will just draw warmer room air in and warm the room, which is not what you want. It is not routinely occupied so does not need an air supply. Just leave it, and keep the door shut as much as possible. Against all expectations our pantry, partitioned off from the corner of the kitchen / diner seems to be sitting about 2 degrees lower than the main room.

Dimmer switch must be LED compatible AND LED bulb must be "dimable" If either are not, you will get flickering lights.

Check that the 2 motorised valves are de energised (the black lever on the side will show you) If both are off, and the pump is running, disconnect the two orange wires from terminal 6 (turn power off to do that) then turn back on, is the pump still running?

Post some pictures of the pump and where it's cable connects to and any other controls like motorised valves, wiring centre etc. Are you saying the pump is definitely connected to permanent L? Is it a system boiler or combi (save me googling it)? Is there a normal "wiring centre" (big junction box?)

No. Jeremy calculated with his really well insulated floor and a low UFH temperature, he was losing 8% through the floor. So a completely un insulated floor would lose a lot more than 20%

You want something like this https://www.screwfix.com/p/floplast-492113-mdpe-reducing-coupler-25mm-x-20mm/14632 I think what you have is mdpe to copper.

As above get a standard tv. Perhaps design your tv wall with an over sized recess surrounded by some form of border / edging so that part could be changed if a replacement was a different size. And for the main tv, forget a sound bar, proper surround sound wins hands down.

Link to the part please? Exactly what is it described as? And what are you trying to join to what? 25mm mdpe to 20mm mdpe? If so it looks nothing like I would expect.

CE presumably meant to say CH as in central heating? Depending on the boiler, the pump should either come on when there is a "call for heat" to the boiler, or some boilers control the pump and have an over run function. If it is on all the time that is wrong. Need more details of the heating system, boiler type, are there any motorised valves etc.

Incoming water temperature makes no difference. It is a fixed heater element that is always on, it does not adjust the power. If the incoming water is colder you will have to turn the temperature dial up, which will reduce the water flow rate to achieve the output temperature you want. Most people don't realise that in the majority of electric showers the temperature know bust adjusts the flow rate of the water through the shower. It could be the rcd function tripping it, that's the trouble with rcbo's, if it trips you don't know if it was over current or earth leakage. It was probably a 7kW shower installed originally. You could just change your 8.5kW shower for a 7kW but you would get even less hot water out of it.

In a perfect world yes. Depends on the reference method, but if it has been working without issue for a number of years with a cartridge fuse, then the cable is probably not going to come to harm. I would start by measuring the actual current drawn in use.

So it is losing pressure but nobody has bothered to try finding the leak?

8.5kW at 230V is 37 amps. It will be the over current function that is tripping, not the RCD function. Replace it with a 40A rcbo.

The regs are different in Scotland, they were not needed in each bedroom just on a landing and within 3M of a kitchen door. I put a couple of extras. Utility room, I want to know if the tumble dryer is smouldering. Plant room / workshop above the garage, it is so far from other rooms I want to know if anything is going on in there. Kitchen /diner was just covered by the one heat alarm. Aico do a heat and CO alarm all in the one package that made things neat in the kitchen diner (gas hob and WBS so needed CO)

AICO without a doubt. And definitely NOT Fire Angel.

It will have a generation meter. So take the reading from that and divide by 12 and that will be the average per year. I hope you managed to transfer the remainder of the FIT contract when you bought it. That would have been a 25 year FIT contract so another 13 years to go and probably something well over £1000 per year. It's will currently be paying over 60p per kWh generated

Before doing much more, I would wait and see if the little bit you have done appears to dry up. i.e. have you really found the problem?

Not that sort, but I have owned and used a "3 way ladder" for years. It has been solid, stable, dependable and very versatile. Several people have told me how unsafe they are, but I disagree. Something similar, but not identical to this one. https://www.screwfix.com/p/mac-allister-2-section-3-way-aluminium-combination-ladder-2-6m/4165x

Depends on the buyer. When selling ours, nothing was mentioned about the solar PV even though the buyer knew it was there. Only now, AFTER the sale is compete am I helping the buyer take over the remainder of the feed in tariff contract.

Or an offset set part on the landing part on the top flight. You might want an assistant to hold them if you are not steady on a ladder.

Can you not get the supply to plot 2 laid in at the same time, but leave the supply head unterminated with no supplier appointed and no meter, hence no council tax trigger?

Probably the opposite "Oh a combi great idea, no hot water tank, plenty of hot water on demand" Until the reality kicks in "Hot water takes ages to reach the tap, furn it down and it gets too hot to hold your hand under, go for a shower and the flow rate is pathetic and it goes either stone cold or scalding hot if someone in the house uses another tap or flushes a loo"

What are your plans? Develop both plots yourself? Sell the plots? build on one sell the other etc? It is clearly best to get services connected to both plots together, and it can take a long time, so I would start now and if you do sell them, they could be sold as serviced plots. What about drainage?

No 1 question is where is the leak and was it fixed? No 2 question is the expansion vessel okay and was it checked. The 2 are very probably related.