Well...tried the app again and was very careful not to touch it and kept checking it to see if it was running and comparing times with the actual iPod clock.
The warm up took 8 minutes to complete and the run not only was running slow in comparison but it actually lost time-at one check is said I had 13 minutes left to go and the next it said 16. I ended up finishing the run 8 minutes before the app (thank god I checked the actual time when I started on this run). The rest of the run and walk actually seemed to run on time, but I kept the screen on whilst it ran down, so maybe it's an issue that happens when you put screen lock on? I've seen reviews that say this is an iOS7 only issue, too, so maybe I should try with my older iPod.
Or I could stop being lazy and set up alarms instead!
The run itself was better than W6R3 but not as good as W7R1. I found it difficult to get into a rhythm (maybe because I was paranoid about the app) and couldn't help noticing my footwork (my left foot seems to land pretty flat in comparison to my right foot which lands much more naturally-maybe I have different length legs!).
But a difficult completed run is still a completed run! Onto Run 3 on Wednesday!