Keep bleating about how the poor sap who didn't fly safely enough on the 1 hr training flight can go and moan to the CAA under Reg 6 and you'll probably end up with all revalidations having to be done by Proficiency Check.
The CAA SRG regulates safety. If a FI has refused to sign a logbook because of safety concerns about the pilot, then the matter should go to arbitration - preferably a Proficiency Check flown with a CAA Examiner at the pilot's expense - with no need for expensive lawyers! Of course, if the pilot should then fail the Proficiency Check.....
So why is there all this whining and gnashing of teeth about this very minor requirement? Just do the trip and enjoy the benefits of some brush-up training. It might just make you safer.........