UK issued (ex-EASA) licences are not automatically recognised in EASA member states to fly EASA aircraft. I've been explicitly told by the Swiss FOCA that a UK issued licence is treated as a "third country" licence and as such would require a case-by-case application for a limited time validation to be issued. The recognition is not mutual. I assume the same applies for other EASA member states but your mileage may vary.