Looking at this closely and comparing it with the oak leaf of the National Trust you can see it must have got something to do with this organisation. I’m imaging it’s some kind of entry token. On the other side is the word Hall ; the National Trust is a charity that exists on a mix of public and government funds to take care of our heritage and the country side. Without this trust many stately homes of historical interest would not be available for the public. Perhaps the word Hall relates to one of these places. Having been in touch with the NT, they tell me that they think it belonged to a children's activity game but not entirely sure; makes sense!