Many a long year ago I rocked up in Heraklion to have a play in a Greek (but ex-Stapleford and re registered) C-150 while I was on holiday in Crete. Two ladies from the Greek CAA insisted my EASA PPL was invalid as it wasn't a "Greek License" despite the Greek flying school owner bringing out a tome the size of a West London telephone directory and pointing out were it was most certainly allowed.
The ultimate solution was to rope in a passing flying school member who kipped in the RHS while I flew around.