All of the above is made easier...

... by the fact that the UK government allows all it's public comms to be freely intercepted by facilities like Menwith Hill which in turn uses the supercomputer based at FBI facility in Langley (US) to look for suspicious activity and profiling. This info will then get passed back to the UK authorities if requested (and as long as it it's in the US's interests, i.e. doesn't comprise thier goals and allows them to keep operating Menwith on UK soil).

Once it's digital it's traceable, end of.