I have spoken to the French dealer who has informed me of the following:-

Actually the boat did measure correctly.

It presented a valid cert at registration and it was accepted then.

However the second placed team lodged a protest after the last race of the series and the kids sailing the boat in the regatta didn't have the cert with them. It was with the French dealer. The Jury allowed a measurement protest to go ahead after the event and DSQed the team.

There is currently an appeal with the FFV to sort the issue.

If you read the comments on the 104 site they all confirm that the boat is in deed a 104 and it should be recorded as the winner. I think that once the appeal happens the results will be corrected.