It's not that simple. You would need to have contract service in Europe and the UK to get in order to get BES service. Everything Everywhere UK (formerly Orange UK) has prepaid BIS service, but not BES.
Your BES server is tied to the PIN of your device, not your SIM, but you still need a BES-capable plan, and that will be nigh impossible to get without a contract, which usually requires residency in the country.
I h8 txtspk.