This has also been running on the engineering forum.There was a recent case in the UK with a guy claiming to hold a licence certifying for 2 major operators.Turns out that he did have a licence a ppl!!!!!Appears that the UK caa (and EASA?) now issue one number per person and if you were to hold a PPL and a maintenance licence the only difference is suffix/prefix letters, the number would be the same.Apparently when found out he was quietly required to leave.Probably working somewhere else now.