When considering a leasehold flat for purchase, would it be a mistake to employ a surveyor who in either part of the management company, or, who has connections with the company?
I think you already have reservations otherwise you would not be asking the question? Remember, this person is working for YOU not the seller. I would use an unconnected third party if it was me.
This may sound a little harsh but when investing your own cold hard cash, take everything you are told with a pinch of salt, do your own research and only employ independent parties to act on your behalf. You will thank me one day