Julian, In the UK it is even simpler than going to a FAA Flight Standards Office, you simply fly on your ICAO PPL, no need for 90 day permits conversions or anything else. (I guess the CAA win this one hands down)
"To a point" If you read the first post you would see the person referred to is a student and does not hold a PPL. Up to 10 hours will count, 35 hours must be "in accordance with JAR-FCL".
[ 22 August 2001: Message edited by: Noggin ]