Didn't get quote, therefore garage can charge what they like.
If it was my garage, and u offered me £500, I'd tell u to poke it and I'd advise u about the £40 a night storage charge until its collected
For real? I wouldn't think so, if a job is meant to take 5 hours, and you charge for twice that without reason or proof, then thats not right, morally and heck, you'd be a star on Watchdog too. If my solicitor charged me 100 hours for a freehold purchase then I would have good reason to complain to the law society as it is well beyond reasonable expectations, even if I didn't have a written quote. There is a level of expectation here, and 11 hours labour to fit a turbo and and clean an intercooler is not acceptable.
Assuming OP telling the truth, then its bang out of order.
I was ripped off before I really started fettling round under the bonnet myself, even got charged £287 for an independent to fit a crankshaft sensor to the wifes old Micra, something since found out I could have done in 15 minutes myself and a £30 part, regardless of expertise, charging 4-5 hours for 15 minutes work is inexcusable.