Thanks FP. I've downloaded a few apps and will try them all to see which works best for what I want to do. Probably fairly sage advice about the first few runs, I think my body almost went in to survival mode after the first one so probably best not to go in too hard, too fast or I'll damage my body or my motivation possibly.
Mate I am in get "ski fit" mode at the moment, so trying to get old bones moving, lubricated and working through a body weight program* whilst getting some running in. If I go as my brain thinks I can, I just get hurt these days
(* You are your own gym - best one I have found by far https://play.google.com/store/apps/details?id=com.leafcutterstudios.yayog&hl=en)