I am planning to self-manage a construction project (single-story extension), with the work being done by independent tradespeople who I will contract individually on a job-by-job basis, completing different parts of the project as funds become available, while keeping overall costs low and under control. I have got full plans and permissions already in place. I am far from an expert in construction, but I have some experience, and I am mostly confident in my ability to do this self-management (although I'm sure I'll learn a lot along the way.)
Occasionally, during this process, I would like to pay a professional to come on site and survey overall progress, answer any general questions I may have, and warn me about any important features of the build that I may be overlooking. I would of course be prepared to pay by the hour for this service. I have asked some local architects if they would be able to do this for me, and they are not interested (perhaps unsurprisingly, since they want to be managing the whole project.)
What sort of professional can I engage to provide me this service? Perhaps some sort of independent chartered surveyor? The problem is I'm not really sure who else to ask, apart from an architect. There must be someone qualified who's prepared to take my money.
I am in the UK.