Can you sell the plates that came with your car?

Please excuse my ignorance and what may seem like a daft question.
I recently purchased a new car and the last 4 digits of the registration it came with are 5UFC which looks like SUFC - Sheffield United Football Club. Whilst in ASDA last week, a gentleman approached me asking if he could buy my plate off me as the first two digits matched his initials and the last four were of his football club. I swapped details with him and told him I'd find out.
I did not buy this plate and it is not personalised, its a DVLA issued one. Can I sell it if I was to buy my own personalised registration or does it always belong to the DVLA? My guess is no, but I'm not sure.

Any advice and help would be greatly appreciated.

Thanks
limonandleme