In reply to elliot.baker:
I have Strava and I'm pretty sure it doesn't do that. I've seen Summitbag which is a Strava add-on which does exactly what I want, but a) it's £12.99 a year to look at activities before my last 100 and b) some of my early hikes might only be on mapmyfitness rather than strava, so I would need to upload GPX files separately, which I'm not sure if you can do.