Look at the RYA website, and go to the registered teaching schools,many of which are in Greece
. They will normally be able to examin you , or if you are looking to sail out there why not do 5/7 day day skipper
course, which if successfully completed will also enable you to get a Icc.
I have been sailing in Greek waters for some time and have never been asked for a certificate. Charter
companies should require them, but I have to say I see on a daily basis some very poor examples of basic boat handling, and seamanship, and so wonder how strictly this is enforced.
it is special.