Not personally dived at St Abbs. Best place to ask is the uk.rec.scuba newsgroup on usenet, I suspect a lot of the people there will have dived there. If your news server doesnt have that group, try the google interface
, not as pretty, but it's useable.
As far as I'm aware, you're not usually as limited over here for your time windows for coastal diving, but you'd still be better off making sure you're aware of what the tide is doing when you intend to dive, be more prepared for it.
And now that's done, off to the pool for the weekly North West Divers training session! Can't wait to sign up for my new job (Diver in the Royal Navy, explosives clearance, woohoo!)