Someone on Reddit thought £100-£150.
Someone on CricketWeb suggested I hang onto it.
I contacted several auction houses, to see what they thought. Hansons Auctioneers said they were not able to help and recommended eBay or other means. Graham Budd Auctions valued it at £120-£150. I did ask if they think it would be worth more if I held onto it, and if so, how long would they suggest, but there was no response, which is fair.
Just not sure what to do with it.