You know you do not have to use the Council's Inspector, and in any event, IME after multi building projects, you will be lucky to see him once.
Our neighbour used an independent inspector for their single storey garage conversion and he turned out to be an absolute nit picking nightmare, he wanted every detail in writing , even down to snow load calculations ! naturally he could very kindly recommend a structural engineer for the snow load calculations at a not inconsiderable sum , he's still waiting for it to be signed off more than a year later
ahem... I was told last month of one claiming he had damaged a tyre on his car on the last visit, so "£300 would make it go away" no new tyres on his car, turns out he had done the same before,
unqualified inexperienced staff wont make a decision,
if the above job isnt signed off the AI will cancel the notice so it falls back on the local authority, needs another application (and fee) and work exposing.