A guy in Guiseley - AutoTechnik, he's ex Audi, and does a lot of electric stuff these days, but did my worn camshaft, cambelt, water pump etc recently, and also the underboost issue (which was a hole in an elbow boost pipe). Anyway, he can be contact via FB messenger https://www.facebook.com/Autotecknik-167668856609093/Mine had the over boost your fairly close where you getting the work done from