Just been reading Building Regs Part A Section 2E..

Because of neighbouring trees the strip foundations need to be a min of 0.75m deep and 0.5m wide. I might be a little over the top on the concrete and not enough on the hardcore, but the foundations will be 2 brick courses below final floor level, thats 150mm or so, so there'll be at least 150-200mm of concrete. Already planned for the insulating fill between the walls, with special sound proofing stuff so I can work in the evenings. Roof will be pitched with internal dry-wall soundproof insulation and vapour barrier. There wont be a ceiling as such because i want to use the roof space.

I need to check with Planning I can have the pitched roof nearer to the boundary than normal; I cant see why not, its already well screened as i said. If I cant get that then it puts the rest of the works in doubt, or i'll have to rethink.