Oz07

Do you mean structurally or thermally? Structurally if they've lasted this long then should be fine. Must have quite a few intermediate walls? Thermally as @ProDave says be a hell of a lot better than nowt. Some modern houses still have 4" in the cavity.

You'd be closer to 4 quid a meter or thereabouts where I live but difficult to say for Scotland

What do you bed your trays on @Nickfromwales

Can you pull your paths away from wall of house by like 2 or 300mm?

Dunno if short for owt but yeh midlands.

Compo here. As in "COMPO ON THE GABLEEEE" no please or thankyous.

I had tanking peel off 1 wall before tiling once. It was the external wall and I wonder if the plaster hadn't dried enough to accept tanking. I stanley knifed up 1 corner and peeled it off in sheets. The 2 other stud walls were fine. It must need a good dry surface to adhere properly. Ive used it on other projects no problem but usually on stud walls

Aco in the potential pond then. Most bco would want to see dpc 150mm higher than external ground id have thought

Is it a truss or a rafter? Not to be pedantic but one is a lot easier repaired or replaced that the other. As it is probably be fine. How far from that horizontal ceiling to a purlin if that is a rafter?

Sounds fine some will do it tight the trays can accommodate the thickness of the tiles overhanging on them usually

Ive seen big commercial renovations where they just use metal stud with rockwool behind and in-between. This is on 9" solid brickwork. Surely if good enough for that be fine for modern cavity?

Yeh my incoming was dirty, the outgoing I just found dusty. It is satisfying seeing all the crap its catching. Expensive satisfaction though

Need a big old hole for the proper site gates. I think heras would be fine without the netting but you want the privacy

You'd use metal studs with the brackets and rockwool its easier than timber stud

Do you change or clean the filters? Mine were washable