So... I went for a 23 mile MTB ride on Sunday with the Leikr - all was fine when I got back, so I long-pressed "save" and turned off the watch.
Uploaded to endomondo... wait, zero length? Checked on watch - yes, also zero length. Both were showing that it took me 3h to travel zero distance.
Not very reassuring.
Also, when will we be able to access our data directly rather than uploading to a third party?