That's a good question for the CAA.
I understand that validity expiry dates are updated by the CAA Regional Offices and/or approved organisations, normally within fifteen working days. It's unclear as to how the a/c Total Hours are reported.
The Total Hours is based on those flown by the aircraft as at 31Dec of the year stated. This figure includes all known flight hours whether or not the aircraft was UK Registered. The operative word being 'known'. I see quite a few registered a/c have older reported Total Hours; it's certainly not just G-AZZR.
If you are the owner of the aircraft you might be inclined to contact the CAA on email@example.com and advise them of what you believe are the correct Total Hours giving them the source of your information. I'd also be keen to understand how this data is reported.
Best wishes, Alex