Where can i sell a signed Chelsea shirt from between 1999 and 2001?

I have a signed Jimmy floyd hasselbaink shirt with his signature on the back and all of the players on the front. people like Zola etc... I was given this by a proffesional referee who obtained it after the match from Jimmy. It has been sat on my wardrobe gathering dust so want to sell it. I don't have any kind of certificate because it was from the referee. i live on the outskirts of London. thanks