Holidaymakers heading for Turkey this summer are being advised by one of the UK's leading car hire brokers that a change in Turkish law means they may face fines and invalid insurance if they drive some of the larger vehicle available for hire.
http://www.prfriend.com/pr/holidaymakers-warned-about-change-in-turkish-driving-laws/Although there's no mention of whether or not the law has also changed for those who passed their tests prior to 1st January 1997.
Driving licence held before 1 January 1997
If you had entitlement to drive cars before 1 January 1997 you can drive a minibus provided it has a maximum of 17 seats including the driver's seat and is not being used for hire or reward. Your minibus entitlement will remain valid in the United Kingdom until your licence is next renewed.