I've not seen any legitimate refutation of the Cass review so far. The 98% of studies critique was explored and rejected on More or Less: Behind the Stats on Radio4 this week. The programme can probably explain it better than me but essentially the trials of "moderate" quality were not thrown out, and were taken into consideration in the results.

Other criticisms seem more like emotional responses where people complain about the language being overly medicalised. Or similarly, the report reading like something from the past where academia considered homosexuality to be a mental disorder. Personally I don't think the phrasing - even if it is clumsy - can delegitimise the conclusions.