Paul,
Your token is quite rare, I have only seen one go buy on ebay about a year ago for around $120. Thats the good news, the bad news is that there are not many token collectors out there. Also these light weight tokens, I haven't been able to determine what the material is, corrode very easily. The 1976 and 1977 London tokens are made of the same material. It looks like yours is slightly corroded also. The original london tokens were dated 1966 and made by the Franklin Mint. All later tokens out of London were this light weight material. If you want to sell it I would be interested. Tom Stroh