Gone West

For a soakaway, have you come across the idea of crates with 'bio filter media' in them to further reduce the toxicity of the effluent. IIRC it was something that I discussed with my supplier many years ago.

I don't know what the actual requirements are, but when we installed our STP in 2010 we discharged to a Klargester reed bed system. Several years later the supplier said the effluent could be discharged into a soakaway. As the reed bed system was quite high maintenance we installed a soakaway.

I wouldn't use a Biodisc. The local farmer had one and it was always breaking down, and it's a grim task sorting it out. There are plenty of STPs with air pumps, which is what we used. Good luck with the job and I hope it finally gets sorted out for you.

Quite a lot of wood treatments are available in sample or tester pots, so I think your best bet would be to try different types on a small area of a door until you find one which is suitable. Do a search for wood treatment sample pots.

They used the box for sleeping in during the day and they hibernated in it during the winter. We put ours under a large shrub, but if yours like the bamboo area then put it there. Your boxes look much better constructed than mine, so they'll probably be queuing up for a viewing. Put a trail camera there so you can keep an eye on visitors.

We were on a narrow single track lane and I wanted kerbs laid along the length of our site to stop runoff from the road. I didn't ask anyone for permission and just got a company in to do the work. That was in 2015 and they just used a couple of signs.

Hedgehogs don't seem to mind homemade accommodation although they wanted to add leaves to the hay that was already in the box. Imag0002.mp4

We used a fire retardant meter board, which is all that is supplied off the shelf. https://www.cef.co.uk/catalogue/products/1939242-24-inch-x-12-inch-flame-retardant-meter-board https://www.tlc-direct.co.uk/Products/TLFB2418.html

When we were building our last house we had one window attacked by a crow which left blood on the glass and sill. It happened every day and in the end we had to hang string netting down on the outside to keep it away. It did work though and I think it is usually a temporary problem at this time of year. We have a lot of jackdaws where we are now and they've never been a problem.

I would go for A2A if it was just up to me, but we will have a new oil boiler. I guess you have a gas boiler at the moment, and if that is the case, I would keep it if there were no problems with it.

Black plastic clicks and clacks when the sun comes out, and goes in. The colour also fades in the sun for the cheaper stuff.

I used Lindab on my last house, but that was steel.

If you don't mind me asking, what make of aluminium guttering is that?

I've been looking at similar units. These are two of the companies I've looked at. https://nextdayrooflights.co.uk/collections/flat-roof-skylights https://skylights.co.uk/product/pitched-roof-skylight-400-x-1500-mm/

How does he justify that? I would take @JohnMo's advice.