I had my boat surveyed last summer for insurance purposes and used a French surveyor based in Sete which is quite a way from St Tropez but he was very reasonable compared to the quotations i was given by British surveyors who work along the Med coast. He had all the qualifications and indemnity insurance that my insurers required and he also spoke very good English.
He is Brit, with a office in UK and Antibes, (you could save on travel expenses)
I'm not sure how familiar he is with 34ft sport boat, ..
it is a good guy,
if you need more info, mobile nr, .. can send on PM