I think I've got it now. In fact, everybody was right.
1) Typewriters didn't standardise on the punct/shifted keys consistently. 2) Adrian and I were right that Apple showed arrogance in ignoring the de facto localisation standard provided by overwhelming MS market dominance over the last 20 years. 3) The Mac user group may well be right that when Apple decided to face it out anyway, they had a look at the issue and decided that there wasn't enough reason to break the UI guidelines by having a poor 'reach' on something everybody used very frequently (double- quote) vs something that was effectively only used for e-mail addresses -- so it's used frequently-ish, but once you've got your machine properly set up with your address-book, you clip in e- addresses or start typing the shortcut name, and don't type the @ itself by hand much at all. Also, now I think about it, the 'double- quote is shifted single-quote' is intuitively obvious. After all, once I got used to not hitting my head against a brick wall by using Alt-F4 to close a running app, Cmd-Q made perfect sense and didn't take long to retrain my fingers at all.
Well, I'm glad that's sorted out! I'll give it a go seeing if I can retrain my fingers to the Mac British layout instead of hacking the keyboard to the MS UK layout -- but maybe 20 years of brainwashing by MS will prove too strong. Dammit.
How's Linux for UI and consistent keybindings? You realise this will have a big influence on whether I feel 'at home' in it, even practising with a LiveCD.
Regards, (...fights the urge to say 'Or do you all live inside emacs and have four hands apiece?' <gd&r>...) Ruth