But what do the UK CAA know about "foreign" licence legislation?
Each member state has different interpretations on the requirements of JAA/JAR.
The only people who know the individual country requirements are...the individual country.
If a "foreign" licensed pilot approaches you for a check/test/whatever - get the individual to check with THIER member Satate.
Then you protect yourself and the pilot who comes to you.
I did one flight for FOCA (Austria) without a problem. Did same again later - different pilot - FOCA had changed their requirements and turned out that what we had done was no longer valid.
FOCA sent a snot-o-gram to the Chief Examiner at the CAA - even though we had done what they previously said.
Get each "foreign" candidate to check with their authorities.
I even get them to bring the correct "foreign" paperwork with them - the national equivalent of the Form SRG1119.