Building control problems

[Kelly1979S]

Hi,
I did a big extension to my home last year and i used an "Approved Inspector" company instead of the normal Council Building Inspectors, thinking Id get a more helpful and speedy service.
However, my project was finished in January and im still wrangling with this company over things. Its been like wack-a-mole. Every time i resolve an issue then come up with something else.
They spent over two and a half months at one point "reviewing" my answers to just five of their questions, after which, they only answered three!.
They seem to avoid directly answering my questions as well.
They also have also been making very overkill demands to which both my architect and structural engineer (as well as contractors i had to bring in) have been absolutely gobsmacked by.
They now want more money out of me to extend my building control time limit with the council and do another site inspection. They are also repeating questions i have already answered.
Im at my wits end with them and feel like they are giving me the run around.

So my question is, what can i do ? Can i transfer control to my local authority's building control ? If so, can they just pick up where the others left off (bare in mind, my project is completely finished!)

If not, is there some form of complaints ombudsmen ?

I feel like they are holding me to ransom :(

It woukd be good if you could.

We pulled out of buying a house that had been extended with the supervision of private building inspectors.

Our surveyor suspected that the extension had not been built properly and we couldnt see that the regulations has Bern complied with on the Council's register.

This turned out to be due I'm to it having been supervised by a private building inspector. All perfectly legal but we didn't have the rights to see the plans, as we, as prospective buyers of the property, hadn't paid for them. It all seemed very odd.

I realise it could have been resolved via solicitors, the vendor and the EA but it put us off the house.