I had the same with a plate I transferred from one company car to another. I was pulled over by a traffic cop for an expired MOT, however the car was only 3 months old. It appeared my registration was against 2 cars at the same time.
Might want to check with the DVLA that the same hasn't happened to yours. Askmid doesn't come up with anything other than N14 MOT isn't currently insured.
Thanks for the offer but I already have more number plates than cars