This week I saw a silver 156 GTA in London, heading southbound on the A3. It took special Alfa geek eagle eyes to spot that through the armco as I headed north
Oh, I had to do a job up near Pentonville prison the other day (don't ask!)...there was a nice black 147 GTA parked nearby
As for the most in one place, I think you would be hard pressed to beat Brooklands the other weekend!