I think it's meaningless and a waste of time. The people in charge today didn't commit the offense, and if you want to address past offenses in UK history, a more important place to start would be at Smithfield anyway. I am more in favor of finding people whose rights are being violated today and doing something about that.
It is not meaningless. There are people in Britain and worldwide who still want to roll back the clock on gay rights. This move would signal that there is no going back by appropriately acknowledging the collective shame that Britain bears for treating their hero so poorly. It is 2013. Gay oppression is, or ought to be, a thing of the past.