Hi red166 and welcome,
have had a few alfa's at this stage ! My last was a 147 2.0 ts have tried all oils over the last 9-10 years castrol, but have found that Mobil 1 Super s 10w 40 is the best oil ever imho. Quietens engine but not the alfa sound
should be able to get it from halfords ... sorry cant give you an exact place but try it