It would appear that there is either a time limit or a maximum number of times that posts can be edited for.
I wanted to be able to keep editing the original post in the European Nationals thread that I started though the option to edit it now has gone whilst I can still edit more recent posts that I've made. (I thought at first that I was perhaps looking in the wrong place since I last edited it and couldn't find the option.)
Any chance of this being looked into so that all the dates can be found in one obvious place? Or if one of the moderators wants to keep their eye on the thread and update it for me then it will save me doing it entirely!