OK, so a couple of days ago I went ahead and ordered (via fleebay) a tin of HARLY WAX car polish ' PURE' NO.1 YELLOW CARNAUBA WAX from these people:-
Woods Automotive
John Woods
12 Churchill Crescent
South Molton, Devon EX364EL UK
Received an email from the seller advising on the best application method etc and all in all, a nice friendly contact.
So, one question still remains and that is prior to all this washing and polishing stuff what's the best way/product to remove those ghastly black marks created by rain?