From someone who used to survey houses for company moves, I can tell you it is an absolute nightmare. You just cannot inspect drains below ground, foundations, hidden services within floors, etc, etc. To do this, you would have to literally dismantle the structure and excavate drains and foundations.
I am now a bit out of touch, but if the builder is a member of the NHBC, then his work is not inspected by the local Building Control officer, as NHBC is supposed to do it, and in my experience their inspections are not as frequent and not as thorough as the Council.
I am disappointed in the NHBC. They are only Insurance Brokers after all.
I suggest you visit the local council offices and go to Building Control, and speak to the person who controls the area of your building. Phone for an appointment first. If he controlled your building he can answer all questions.
I hope I haven't disappointed you, but insurance for a house surveyor is extremely expensive, hence the "get out" clauses.
Beeches.