Only kidding mate!
I guess number plates are one of those things that are only worth what someone is willing to pay for them. A certain set of numbers/letters may be worth a hell of a lot more to one person and nothing to another.
If this was my plate, I'd probably advertise it for a reasonable £300ish. People always think their number plates are worth a lot more, but I found from previous experience they are difficult to sell for a decent price.
Realistically you should be able to achieve around £300 for yours I'd imagine.
Good luck!