is it any good making an official complaint about kwikfit fitters.
Doubt it.
They do not care how many hundreds of motorists complain about their services and how often they are highlighted unfavourably on Watchdog type programmes.
Many times I have forcefully voiced what I think of them face to face in their garages. Last was at the Ashford garage the other year, when I told everyone listening, including potential customers, how they fiddled their customers and conned them into unnecessary work. Customers walked out, but no manager or member of staff stopped my "assessment" or asked me to leave, because, I suggest, they knew it was all true!
So, complain however you like, but it will make sod all difference, apart from making you feel better!