If you change your nick, lol!
Be aware though, the UK is very region and class oriented when it comes to accents, slang and speech in general.
I'd be very cautious to start using slang which would single me out as either working class or upper class - likewise any particular region unless you actually live there... This takes out at least 50% of all slang you could use.
So be careful with that, you will just sound silly if you get it wrong. (I know from my own experience....)