If you had been here a while Trader habib, you would know that CAP413 is the EK standard for all radio work on an EK aircraft. So the Brits are correct
CAP 413 is for use in UK airspace only. I believe (but cannot prove) that EK, like many other ICAO signatories accepts ICAO Annex 10 as the R/T authority. Perhaps this mis understanding is a result of outsourcing training, how can you maintain a standard when you do that?