Welcome to the ranks of Supreme Sunbeam ownership! You ask for suggestions on where to begin with its return to life.
First, locate the local money changer. Practically none of the sources will accept dollars or credit cards. Thomas Cook is one I've used (call 1-800-287-7362 for the one nearest you). They sell foreign currency travellers cheques without commission.
Starting with the Good Book(s) will save you a lot of time, aggravation, and money (especially of the pound sterling variety).
Must haves are the shop manual and the parts manual. Shop manual gives all the specs and how-tos, the parts book is most valuable for the drawings so you can see what the shop manual is talking about. Jim Wilkinson sells reprints for about 25 pounds each. His address is "Backacre", 40 Hollybank, Ackworth, Pontefract, West Yorks. WF7 7PE U.K.
STAR (you did say you had joined) has a Technical Tips Manual with extremely valuable advice. A new supplement is expected out shortly. The editor of that is Philip Chapman, 65 Downs View Road, Hassocks, West Sussex, BN6 8HY U.K.
Then, when you start to work on the car, it goes a lot easier with the proper tools, although SAE and metric are "close enough" for many tasks. Call Phil Brown at British Tools and Fasteners (805) 528-0418 or e-mail BOLTNUT(at)ix.netcom.com for a catalog of Whitworth and BSF stuff. He's in Los Osos, California and does take plastic.
Now, you'll be ready to start spending money on parts. Colin Mumbray's Sunbeam Talbot Spares probably is the most comprehensive source. His ad runs in your STARDUST magazine and a new catalog is sent out with it at various intervals.
I think you will enjoy the adventure
"Ole"