A bit of a strange one, but something that is worth considering. Basically I've done London twice, and both times have sold my medal on ebay in the following days. In both 2010 and 2011 it sold, buy it now, in 1 hour, for £50, and the next year £60. This year I will be listing it from my mobile that evening at £70.
If you aren't sentimental, then it is certainly something to think about, as £60 after fees is a lot more useful than yet another medal to throw in to the cupboard.