Unfortunately, in this country there isn't a universal aircrew id badge. A BAA airside is a good start but try flashing that at Liverpool.
Your operator will supply you with a security badge linked to their operation for aircrew but if you are on ground ops you will need an airport pass. BAA is shrinking - LGW gone - EDI gone - STN going so unless you plan to be at just one site you may look like a Russian General!
Out of curiosity why are you looking for work here when most of us think Aus looks far more appealing?