This is 'just' a regular British commemorative coin. Mintage is 3.400.000, so not 'special' in mintage numbers, and it's from 2011, so not 'ancient' or having many coins destroyed already over time due to various circumstances. If your coin isn't in a Fleur de Coin condition, I'd guess the price would be much, much closer to the £1 you found than the £1000. In fact, to most people it'd be worth just 50P...