ProDave

That's the plan. we did that in our last house, set the tiled hearth exactly level with the wooden floor of the rest of the room so you could walk on the hearth without noticing it, yet it performed it's function. I seem to recall BC mumbling something about there should be a step but never made an issue of it.

It was obviously not fully closed then.....

I have just measured ours, and it is 900mm to the underside of the worktop so more like 940 to the surface. Even at that height the kickboard under the dishwasher needed a notch cut out of it. I chose that height so the kickboard would go under without cutting it. any lower and the kickboard would have to be trimmed which must have been the case here. You don't want main units and island at different heights, That will just look silly. So the issue was you did not explicitly say to the architect what height to set the units, the architect made a decision to what he decided was "normal" and the fitters followed his instructions. You will say it was the architects fault, the architect will say it was your fault for not instructing him. Go and search all your drawings and documentation, if you can find anywhere that states the worktop height you might have a case.

I don't see loop length has any bearing on flow rate. Flow rate is determined by the heat output you need. e.g it does not matter of a room has 1 loop of 100 metres or 2 loops of 50 metres, each loop will still need the same flow rate to achieve the same heat output

More of an issue is it might be too low for a washing machine or dishwasher to fit under?

I have edited my post above to show some links to the underground storage tanks. The other half of that setup is the above ground storage tanks by the shore. https://www.28dayslater.co.uk/threads/seabank-tank-farm-invergordon-02-08-09.42247/

There is an interesting "facility" up here, old oil storage tanks hewn from solid rock in the hillside. Presumably they are vented to the surface, but i wonder if the vents were capped how well they would do as pressure vessels. https://en.wikipedia.org/wiki/Inchindown_oil_tanks https://www.atlasobscura.com/places/inchindown-oil-tanks

Make sure the join lines up with something, e.g. the exact centre of a window bar. If we had had to have a join in the upstand it would have been exactly in the centre of and behind the tap, which is NOT at the mid position of the upstand.

Is that laminate flooring? If so I would be inclined to cut the laminate flooring and just install floor tiles straight onto the timber floor of the shed, there will be no or minimum step from the laminate to the tiles and so it will feel like the hearth is not intruding into the floor space.

Is this a sill or an upstand We had a granite upstand 2.6M by 15cm tall and 20mm thick. It took the stone company 2 goes to cut it, the first one snapped. They warned us if the second one snapped they would have to do it in 2 pieces. So I think you would be lucky to get 4M in one length. I was glad we had ours supply and fit, if it broke getting installed it would be their problem.

To be honest, if it's due for demolition, I would just do it, nobody is going to check or care. Alternatively, what do you plan to have in your new build? If you are going to have an unvented hot water cylinder, buy that now, and put it into the old house (you could even feed it from the header tank as a vented cylinder for now) .

As long as the electrician is doing "loop at switch" wiring, which is pretty normal these days, then all you need to decide right now is how many light circuits in each room, and then in your vaulted ceiling room just leave a long length of the switched light feed cable(s) ready to be positioned before the ceiling covering goes on, once you have decided what you want. Decision time is just before plasterboard or other ceiling covering goes on.

Squirt a 50% bleach 50% water mix in the gap, leave for a while, then rinse out with fresh water. It will be as clean as new.

If rainwater started to pool on the solid cover, it would soon run along one way or the other to a slotted part of the drain and drain away. Who will be doing these surface water drain tests? I have never heard of that before.

P.S for anyone reading this thread, this was my completed wall complete with cylinders, and building control had no issues at the completion inspection:

Lift out the slotted drain cover under the cylinders and 2M either side and replace with something solid, even treated timber, sealed as you insert it, should do. e.g. I would start by looking at decking planks and see how close they are to the required width and could they be planed or sawn to the correct width to drop in?

I personally hate "plastered on the hard" brick walls and chasing cables into them. When I moved to Scotland, where the majority of houses are timber framed, my job became very much easier. I would suggest you consider lining your brick walls with 25 by 50mm battens vertically and fix plasterboard to that thus creating a service void for cables. You could even add an extra 25mm of insulation into this service void as long as you leave a strip clear for the cables. Your electrician who has probably never seen this and is used to bashing grooves in brick walls for cables will be enlightened and will want to move to Scotland for an easier more pleasant life.

Make sure ALL the outlets you need, power, aerial, telephone, network etc are on the wall behind where a wall hung tv will be. Think about set top boxes and surround sound etc, where will those go and how will you route cables to them? All the portable stuff most is wifi now so just provision for enough sockets to plug everything in. My favourite recommendation is run socket cables horizontally from socket to socket around the room. As long as there is 1 socket on each wall you have a safe zone all the way round so you can easily add extra sockets later if you find you need more.

That is too much like a piece of string. Kitchens vary enormously in size. Just about any budget kitchen retailer will offer you a set of kitchen units for under £1000 but it will not be the kitchen you want.

Is this connecting to mains sewage? the usual solution is just a holding chamber and a pump, sometimes 2 pumps for redundancy.

Context please. Is this a new system that has never worked properly, or it has previously worked perfectly but started to misbehave? The 2 switches on the tank are probably immersion heaters. If you are heating the hot water from the boiler these should both be off. Post a picture of the tank and the switches to confirm that. Also post any pictures of anything else related like motorised valves?

Well done and that's a pretty impressive build cost.

Whole window Uw value will go into the SAP calculations and that will pass or fail building regs. Manufacturer should publish Uw values.

My guess the G/Y earth was a later update. for me it's the screwits that date it.

If you are feeling a draught from a standard ceiling vent, I might suggest that your system is not set up properly and you are running at too high flow rate.