So, an update.
Went back to the garage and had them listen to it. Apparently it is the turbo waste valve.
We took another 2.4 Qtronic out which did the same thing but I would say the volume of the noise was maybe 25% of the noise in mine. It was a bit frustrating as the car didn't present the noise on the test drive or on the first few days I had the car, but there we go.
Anyway, just want to publicly praise the guys at Chris Variava. I don't think I can live with the noise and they have let me take a 2.2 petrol Brera home to test and will let me swap it as per the Alfa used car agreement. Will and Paul were both very accommodating and I was very grateful for this.
Couple of questions.
1. The car I might swap to doesn't have Blue and Me... can this be added as an aftermarket? I need bluetooth really
2. Has anyone got any experience of remapping the 2.2 petrol? It is quite lively already but I am interested to know if I can improve the BHP and MPG much?