Welcome Just.
Where are you based?
I have a Lawil and a few contributors have Willams so there should be some help available somewhere amongst us.
Spares in England are going to be thin on the ground.
My Lawil is stored a long way from my base so I can't check to see what you are talking about - any pictures?
I don't have any spares. I have been told that many parts are shared with Fiat 500 but I doubt the drive shafts are the same as the Fiat is rear engine.
Lets hope there is some knowledge on the forum and that perhaps our French friends can help.