Odd. I recall AOL being around in 1990 - I think via a separate UK service provider. I never actually used it, so memory may be playing tricks.
If AOL is growing in the UK, I'm surprised.
Wikipedia has its usual problems, but gives an insight into the difficulties it is facing.
Carphone Warehouse, which bought AOL-UK, also operates TalkTalk. Both are in the "lower half" of the customer satisfaction ratings
here.
I believe AOL offer "free" connections in some circumstances - maybe that bit of the business is growing?