ProDave

So you are wanting to build a house over someone elses access / parking space, so someone else will be parking their vehicle under your house? That might be "interesting" for insurance. Where will you park your car?

Check with Joule that their heap pump is inverter driven. If not it will be more noisy, and a little less efficient.

That is my issue. £600 for a box containing a water to air heat exchanger, a fan, and a drip tray to collect any condensation. For that money, you can buy a complete air to air ASHP aka an air conditioning unit.

If you can get something under there to support it before it collapses you might get away with it. But it won't look pretty. You might want to think about rendering the finished wall? Why have you lowered the soil level that much? you seem to have exposed house wall brick that were never designed to be on show, and is that the top of the house wall footings now on show?

It looks to me like those steps were build on very thin foundations direct onto the ground, and at some point someone has lowered the ground level somewhat undermining what little foundations it had to start with. It is staying put by a wing and a prayer and not doing very well judging by the crack. If you want to keep the ground level that low you need to dig some fresh deeper footings and rebuild the whole wall.

Connecting it to a battery on the micro amp range might not work very well.

Seriously, think again about radiators upstairs. That will force an ASHP to run at a hotter flow temperature than it does with UFH and it will be less efficient and more likely in cold weather to defrost. Instead fit UFH upstairs, either using the aluminium spreader plate system, or if you design the joists for the extra dead load, using a pug mix screed system. A lot of us, in very well insulated houses find you don't actually need any heating upstairs. I provisioned for small electric panel heaters in the bedrooms and have not fitted them, the electric points remain there, unused.

Serious suggestion. Air source heat pump to under floor heating. This will keep your house warm all the time, in a well insulated modern house that retains it's heat well. Then a well placed (i.e central) wood burning stove. This is what we have. Constant 20 degrees form the ASHP, but if we want to indulge, light the stove, open all the doors so the heat circulates throughout the house, and it's quite possible to quickly get the house up to 23 degrees or more.

I can't contribute to the question, but I looked for a couple of FCU's a while back (to add cooling to our house, UFH used for heating) and found them both hard to find, and very expensive for what is a very basic piece of kit from a technical viewpoint. So if you have found a good cheap source please share.

They have accepted the ramp but not the detail where it ends (to be fair there is a big step there at the moment) Eventually that will be tarmac, when we get around to it and can afford it. It is likely I will try for completion with iy just being gravel and levelled out. Plenty of houses here have concrete ramps ending at gravel and are passed.

You WILL need planning permission unless the land already has planning, or a certificate of lawful development, for a "Caravan" It is building regulations that a portable building is exempt from, but the drainage connection still needs building regs. If your building is truly mobile then you can use it for 28 days each year without PP then move it to a different location. If it was as simple as buy a bit of land, put a caravan on it and live in it without any permission, the whole of the SE of England would be full of fields of caravans.

Pour the foundation wide enough to give flexibility. You DO have permission for the foundation to go under part of next doors garden don't you? Then seek written confirmation from the neighbour before starting to build the wall if the wall of the extension is able to be built right up to the boundary (and no fence will be erected on that part) or if a fence MUST go back you will have to leave room for that. I thought this all should have been agreed before you started? Assuming an identical pair of semi detached houses, I would have said the mid way point would be determined by measurement, not by the position of a fence that might not even be in the correct position?

I set aside the whole of the roof space above my garage as a "plant room" The MVHR unit goes in there. For the ASHP there is a wiring centre, a circulating pump, and the expansion vessel for the heating circuit. That is it. We located the HW cylinder elsewhere. Putting it in the original intended location in the plant room would have resulted in a very long hot run to the kitchen, so instead we created an airing cupboard in the corner of the small spare bedroom that puts the HW cylinder central to all points of use and very much closer to the kitchen. What I am saying is don't get too hung up trying to put everything together in a plant room. Some things are better being spread out to locations that best suit the item.

So the blue line on the plan is underground? How do the neighbours get the supply across the road? Overhead or under?

If you have an HV cable on your side of the road, beware of clearance for delivery trucks, cranes, scaffolding and building exclusion distances.

Yes you can cut the pipe but it will be awkward to get in there and do it. As long as you grip the middle bit of the valve, the bit with the screw that you turn to isolate it, while undoing the top nut it is easy. then you just lift off the basin still with the pipes connected to the taps. You would need to cut the pipe to the outside tap as well. If you don't might fighting with little more than just a hacksaw blade (as I doubt you will get the frame in) you could just cut the pipes above where the outside tap joins.

Progress. Common culprit is a pinched cable. Remove each socket in turn, check for obvious damage or pinched cable and repeat N-E test. If not at a socket, vermin damage underneath the 'van is likely, them mice love eating PVC.

Corrected.

Yes turn both those isolator valves off and undo the pipes above them. You need TWO large adjustable spanners, one to undo the top nut and one to hold the body of the valve to stop it turning. Gland pliers will do the job of holding the valve while you undo the nut. It you remove the trap, tape over the end of the waste pipe with duct tape to stop smells. What's the pipe going through the wall under the basin? Whatever that feeds will also be turned off.

You can get timers rated to switch an immersion heater, but I have never seen a thermostat rated that high, you would need to use a relay or a contactor.

What are your floors made of downstairs?

Well at least try with your multimeter on ohms range and see if you get any reading between N and E or L and E on the now disconnected ends of that ring main.

So what test equipment have you got @Tom?

60 (upstairs) is very high for UFH My guess is the problem is just the temperature is too low to deliver enough heat, and I bet before changing the mixer, the old one was set much higher.

I take it the plumber is not invited to the house warming party? Hope you get it sorted