I've used Eaglesham in the past and very good reliable garage but being an approved servicing agent rates are more expensive. It would be worth sending Duncan at Hypertech an email detailing the problems and getting a rough idea of a price for the work.
When you bought the car did the guy say anything about the car being mapped (imports don't run properly on uk fuel). What other mods are on the car, decat, induction kit, etc. Also was the turbo a direct swap to match the original or is it different.
Sorry for all the questions, more info we have the better we can advise.