In my opinion, the only people who know about the building regulations are those who write them (but never see how they work in practice), those who teach them (but only know the rules), and those who are meant to stick by them (us non-cowboy tradesmen) but are not allowed to force customers into sticking to them.
Any slip up along the way will come back on us (not the customer who's responsible for his/her property), nor the tutor (they've not seen the circumstances), nor the regulation writers (who only write the rules).
Solicitors, when it comes to buying a house, like to see a piece of paper but have no idea what they're looking for to ensure things are up to standard. Surveyors have knowledge of all the rules but not enough knowledge in any particular area so wouldn't know if a flue might leak or an oil tank base is large enough or whether the earth cable is working correctly or whether the timbers in the roof are the correct size. Local building inspectors can be good (and give helpful advice) or, more commonly, useless and tell you that if you're a member of a competent persons scheme then you should know how to do the job properly.
Etc, etc, etc.
What's this all for? Jobs for the boys, of course!