A TINY marking on your £10 note could make it 1,700 times more valuable. The key is to watch out for the prefix "HB 01" in the serial number, located at the bottom right corner of the note. Collectors highly prize notes with specific serial numbers, and the recent auction highlighted just how valuable these can be. The star of the auction, a note with the serial number HB01 000002, fetched the highest price of £17,000. As more notes featuring King Charles III enter circulation, the chance of finding a valuable serial number increases.
