Conor

You'll want it to be insulated, and built quickly and simply. ICF would be my choice. We'll be doing the same as well soon.

If there is a chance of water flowing the road in heavy rain, then you want to plan for that. We re-laid the road side kerbs so they were sitting 20mm higher than the road, and put in a bitmac apron with a fall to one side. For the rest its gravel grids and 14mm stone. Works well, no need for any additional drainage. you could lay a short section of channel drain. If you wanted to use grids, all you'd need to do there is smooth the surface out, put down a skim of sand or dust, then the grids and gravel. Loose gravel on a slope is just a waste of time.

Are you using glycol? Inhibited glycol should be all you need. And water, obviously.

Jetting attachment for a pressure washer. Don't be surprised if the blockage is due to a broken pipe. Endoscope camera would be handy. What are those other pipes discharging in? Anything from a kitchen sink or dishwasher? Could be fat build up in that case.

I had 5tonnes of sand and soil to move to the back of the house two weeks ago. we deliberately ensured we have vehicular access to all parts of the garden. I hitched the trailer up to the car and got shovelling

You need undercoat. Then a single coat of good gloss usually does the job. Paint before fitting. 10x easier.

We ha da ICF build, but wanted another 100mm EPS on the outside to get to passive house stnadard. The builder used 50mm PIR instead for the lower floor. So I over boarded those sections with another 50mm EPS. Used 100mm EPS on the upper floor that wasn't in the builder's scope. You wont be able to render onto the PIR. Options are to fix cement (render) board, or a thin layer of EPS. You'll need mechanical fixings. No need to take the PIR off.

You can get a 7kW charger for £300-£500. Virtually all EVs have a type 2 socket, and that wont change any time soon. Only exception are the 1st generation Leafs, Zoes etc, so no worries about compatibility. Your spark has done all the hard work, dead easy to install the actual unit.

About a third off.

Do you use the garage? If yes is there scope to build something like this outside of the bungalow? I'd move bedroom 2 into the garage, widen hallway and put the bathroom in the middle. You can then move the ES into the old bathroom, make bedrooms 1 and 3 larger. Also look at repalcing conservatory with a proper structure. All depends on what you want to gain and how much you want to spend.

That's a good price. 0.002% of your build cost....

You can move in whenever you want, just check with your insurance company. Our self build policy allowed to live in the house, and only lapsed once we got approval, then immediately got normal house insurance.

Pretty much how we did our ramp/steps, well compacted ground, a good thick mortar bed. Down a year an dno sign of movement. BUT... make sure there is drainage out through the side walls or else any water will make its way up through the pavers.

We've four bathrooms, only one has an opener, it's never opened.

+1 for sticky stuff remover.