David, another American who does language research in the UK, has blogged about something I've been meaning to blog about. I'm trying not to hold it against him, because he seems like a nice (AmE) guy/(BrE) bloke, and you should read his entry. The issue is how people read out or recite strings of numbers, such as phone numbers or credit card numbers. Take the number 8853, for example. Americans typically say that as eight-eight-five-three, whereas a BrE speaker would be much more likely to say double eight-five-three.
David's entry talks about the cognitive dissonance that he experiences when he is writing down a number and has to translate from double 8 to two eights. I completely identify with that feeling--it feels like the information is coming backwards. They say two, you write 2, but when they say double you have to wait to hear what you need to write and then write it twice. And when someone spells a word and they say double-u, you're expected to write W, not UU.
All the same, it is an aspect of BrE (and other Es) that I've embraced (my phone extension at work is two sets of double numbers), but one that's also led me astray. When I lived in South Africa, I had a credit card number with three zeros in it. Reading it out to people, I'd say seven-nine-triple zero (or whatever it was), which usually led to some consternation. People were used to hearing double zero, but triple zero didn't sit right, and they'd ask me to repeat the number. I think I made single attempt at quadruple four for another number, but that didn't go over well at all.
So, I've stuck with the doubles but given up on the triples and quadruples. (Nowadays, I say double four, double four when faced with 4444.) Better Half claims that he'd definitely use triple and might even use quadruple--but that he is extra careful in reading out numbers on the telephone and says "four [pause] four [pause] four (that's three fours)". But now he's added "I'm not sure I'm the best person to ask about these things." So, what do you do?