I loaded up ninthace's
GPS trace of Gowbarrow Fell and noticed a button at the bottom to the left of the middle that says 2004 and when you hover over it it says "Click to view historical imagery" or something like that. So I clicked it but ninthace's GPS trace vanishes. There's now a slider at the top of the screen that has two tabs and a scale of between 2004 and 2018, the front tab drags the back tab along with it but you can move the back tab independently anywhere behind the front tab. Anyway, it seems to adjust the year the imagery is from but it also adjusts the year that the GPS is shown from so that if it's before the GPS was taken then the GPS trace doesn't show up.
Is it possible to view ninthace's GPS trace on the 2004 imagery without editing the GPX file and changing all the dates to 2004?