As a serious answer, I don't know when the last official batman was retired. But a mate of mine was attatched to the Ghurkas in Hong Kong, he didn't have a batman, but a Ghurka did all his dhobi and polishing etc etc.
He reckons it was so the regt wouldn't be shown up by a badly turned out rupert.
Adam West was the real Batman, currently showing on freeview channel 24.
Another serious answer. As far as I know officers on public duties in London still have batmen, or orderlys to give them their official title. Also as far as I know senior generals such as the CGS also have them. I think, at least in the past, that the officer had to pay him a certain amount each week on top of his normal pay.
Hope this answers some of your question.