Mr Punter

As far as foundations and NHBC / LABC go, for retained or proposed trees it makes no difference on the size of the tree, just species, proximity and soil type.

I don't see dry lining contractors using collated screw guns. Maybe @nod will comment as it is his field. A friend bought one and it was prone to jamming and the screws are expensive.

Or these bits (and I have certainly done far worse):

I would have thought plasterboard and skim would be OK. Why did you rule it out? BTW that is a VERY impressive range of back boxes on the left!

Oh dear I was using the paved are data. Should be 2.64!

Yes as @JSHarris says. Assuming the most negative you would have 0.016l/s/m2 so 0.016 * 120 = 1.92l/s. Can I have some of the £1,350?

I think metal stud for ICF and brick and block, timber stud for timber frame and I would get the TF company to do it. Get them to quote to insulate the walls as well.

I have only ever done floating chipboard over a solid floor, as I would fear the joins weakening if not fixed to the joists. We used a product called ScreedBoard in a flat conversion. It is an overlay board with a soft backing so you would fit this over your chipboard. The sound test results were excellent.

Drain rods or Cobra rod must be easier than digging and then making holes in the pipe.

Drain rods without fittings (you may need to borrow some extra sets) will let you establish where the blockage is.

Access seems pretty good. Was it garages on the plot before? Well done on the VAT. It is easy just to let these thing go and regret it later. Hopefully the weather will stay good for you.

I think it is worth waiting a year, unless there are bits that will be a real pain to get to later on (like your swimming pool ceiling or the tiger enclosure).

I find multi tools and petrol strimmers much noisier than impact drivers. And Paslode guns indoors.

I had not heard of the oil pulse ones. I have a Makita and it it great for driving in coach screws and long timber screws but never used for more than an hour at a time. The oil pulse ones sound good for plasterboard but I would never use it enough to justify one.

Nice drawing Ian. Like @Construction Channel says, cut the studs straight as it is simpler. You can wedge a bit of batten in the gap at the top to get a better fixing to the rafters. The top row of pb screws will still be fairly close to the top of the board. Are you building the wall on the floor, then raising it?

Normally it is one vent per room. Some systems have a manifold and smaller ducting.

Did you also price this in brick and block @Humpty Dumpty?

Yes but as @Russell griffiths suggests, use a planning consultant to do your talking.

I am not quite sure what I am looking at here. Care to elaborate?

You only need to demolish the existing bungalow to lock in the as-yet-not-applied-for consent for a replacement dwelling. Your planning consultant is best placed to deal with the application.

Their job is to approve applications that comply with local and national policy. Ask you planning consultant what they think. If you got consent for a new dwelling, you could demolish the bungalow. The consent would then be locked in.

It may be worth applying for a knock down and single new 3000ft2 dwelling as a halfway measure. If it got consent, the planners would then have to view a subsequent application for 2 dwellings against this.

The master bed looks a bit small and I don't like the en-suite through the dressing room. Did you think about having the master at the front, beds 2 and 3 at the back and perhaps doing away with the guest suite - a sofa bed downstairs maybe? Not if you are selling on though as the current setup will be worth more In the family bathroom a double sink is handy.

Nice dry settled spell here - hopefully he can make decent progress.

Is the silicone applied to the outside?