There's Classicarco in Worsley, not got the number but will be on Google. I use Gavin at ICS Service Centre at Eccleston, 10 mins of J9 M61 or J27 M6. He has the Alfa Examiner diagnostic tool. His number is 07786 834098 but he's on holiday this week.
I used to use Alfatech in Huddersfield when I worked over that way. There really good (and pretty reasonable) and seem to know their Alfa's, but after changing jobs I didn't fancy travelling that far.
You could try Gus at Alfatune in St Helens if you are prepared to travel. He knows Alfas inside out and his cars regularly win in the Alfa racing series. He has serviced my road car for a number of years.
