OK.
Starting in the South West (Cos that's where I be frorrm!!)
www.allaudi.co.uk
All Audi in Bristol. - A lot of modern stuff but do also have some late 80s/90s spares quite often.
www.audi4u.org
Audi4U - Down in Bridgewater, Somerset. Very helpful chaps. Do carry parts for 80s spec cars. Not much older stuff but have a good knowledge of their subject and interchangeabilty (word?)
www.vwaudibreakers.co.uk
Based in Melksham (Wiltshire). Lots of experience - again they are specifically looking at 1980s onwards but will be able to provide advice on what should fit where.