So I tried my luck with a different garage and it looks like they may acknowledge my request to get it fixed under warranty.

Apparently our cars have double synchros which often cause this problem. He said the problem is normally resolved by replacing the double synchros with a single one.

Now, to be honest I'm not entirely sure what a synchro is but I'm surprised its possible to replace a double with a single and if the single works just as well then why do Ford bother fitting a double one in the first place?