Its certainly not used nearly as much as in US English. Zebra obviously, xylophone is spelt with an X though! Its in things like haze, azure, zoo, etc but its definitely the hardest letter to get rid of in scrabble! (unless you have a Q and no U!)
The other one that interests me is we have words ending with -OUR and your words end in -OR like labour, colour etc.
If you are fascinated by UK accents you want to study Irish ones! I had friends from college who were from towns only 100 miles from me and they used words (and had surnames) that I had NEVER heard of. Some Irish accents are impossible. And for the record NO-ONE in Ireland speaks Hollywood Irish..top of the morning to ya! (think Tom Cruise in Far & Away) My accent is very Irish but not really connected to any one place in Ireland since I am away from home 11 years, 5 of which I spent in Limerick in the southwest and the other 6 I spent in Dublin (until I spend a week at home and then it goes back to my Wexford drawl where noone pronounces the T at the end of a word or the "th" in the middle Goodnigh' or somthin')
Nat- have you a real scouse twang...like Jackie Corkhill?