Any EASA medical examiner may carry out a medical on any EASA member states licence holder. I hold an Austro control licence and have my medical done in Spain.
Even the LBA have become easier to deal with when it comes to a SOLI and will now release records.
Any EASA examiner my conduct a test on any EASA licence holder by following the EASA Examiner DIfferences Document. There is no longer a need for on line courses are separate approval. Follow the document, file the notification and do the tests. I do dozens every month on licence holders from all over the EASA domain including the UK.
EASA are actually pretty easy to deal with. There are still a few quirks but generally its pretty smooth.