Good spot GL, however by 'operator' I mean pilot (should have made that clearer my apologies) and I doubt that a pilot wrote the job spec, probably written by an HR type who can be excused for their naivety.
If you can find an official EASA document that refers to a 'frozen ATPL' then you're looking harder than me (not difficult) but the fact remains that no pilot will ever possess a licence which has 'Frozen ATPL' written at the top of it, they wil have either a CPL with a number of ratings endorsed on it or a full ATPL.
The term 'Frozen ATPL' is a slang term that has become common parlance..........innitt!!!!!!!
Cheers
M