@OP, I hope it was not recorded delivery and you signed for it.
If it was plain, then ignore it and watch what you sign for.
They will send letters galore you can ignore and then this shoddy U.K. company will buy the fine and send threatening letters to you which you ignore.
Check how long they need by law to send a letter to you by recorded delivery and how long till they forget.
Germany is 6 months, Italy 360 days-just don't sign or acknowledge or visit Italy for a 2 yrs.
France-well Google it and if you visit or drive there you risk getting stopped and pay fine.
Not going to France for a few yrs? forget the fine and don't sign any letters.
Signed? you're stuffed and the fine goes up if you don't pay sometimes.
Don't speed and don't drive in Italy Florance like I **** did.