Martin Carroll wrote:
What are the consequences of not notifying Building Control about
notifiable work?

Plumber friend of mine is putting in a unvented system (he has the
qualification to do this) and asked me if I knew what the would happen
if he didn't put the building notice in.

If the property owner tries to sell the property (s)he will be asked for
proof that the work has been authorised. If the owner cannot produce the
documentation then they will have to pay to get it inspected and approved.
It is much easier and cheaper to get it done according to the rules.

Peter Crosland