Idemnity Policy

[Goyambokka]

I own a flat with a mezzanine level. The surveyor thought that building regs had not been applied for when it was built and would not be granted today. It was built more than ten years ago,
but not before 1983.
My solicitor suggested a Building Regs idemnity policy which I have.
My tenants are concerned that it is not safe because the floor boards bow a little and want me to send someone to look at it.
I'm happy to do that, although I personally don't think it is dangerous.
Who should I ask to look at it?
A builder? Another surveyor? And ideas at all appreciated.

[Goyambokka]

Thanks Zacsmaster.
Sounding very expensive already....