Unless its "as struck" £20 or £30 ....then it won't be worth a lot. If you can clearly see Victorias hair detail,a sharp image of the Union Jack on Britannia's shield,there are no edge knocks,the date and lettering are all clear and it HASN'T BEEN CLEANED. It maybe worth £3 to £7. A worn coin but with date & lettering clear ....maybe £1. Still thats not a bad return (there were 480 to the £)