AUK allows its members to ride a DIY anywhere. We wouldn't know if that ride was an overseas, non-AUK event, and I doubt anyone would mind. It might look perhaps a little indulgent to validate the same ride here and there, but I think that's a decision for the rider to make.
Someone else has asked about doing this recently, btw, but I'm uncertain anything came of it. Another rider asked about claiming a UK ride, but that fell through as it became apparent that the two rides were incompatible. Can't remember the exact details, tbh.