Hi John,
The 17 digit number is for the international VINnumber. I think Morgan adopted it when they gained full EU approval in 1998.
Your experience is concerning as the dealer regularly advertises in Miscellany saying they are in need of new stock! Not as keen asthey make out? Surprising as they also advertise 1960 plus 4s that will not have 17 digit numbers!
They I pressume, will also offer the suit case promotion if you buy a new Morgan.There is a message there.
The Morgan world is changing, but there are still friendly dealers out there, who have been around since the 70's,and are not put off by a 4 digit chassis number, but they may be a dying breed!
Best of luck with your decisions
Clive
