I've had many 'off road' plates done and just by glancing at your rear I'd think it's illegally spaced. Characters and spacing between characters look right to me, it's the vertical edges to the first and last characters that look less than 11mm.
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/955014/vehicle-registration-numbers-and-number-plates-inf104.pdf
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/955014/vehicle-registration-numbers-and-number-plates-inf104.pdf
You will get done here for having a plate not issued by the Dept of Transport, or altered in any way, but thank god our state government has had the wisdom not to implement MOT's. A number of states have them.....road toll's the same.

