Well I have surprised myself. I did W3R1 on Monday evening, managed all apart from the last 3 min run, did 1 min, then fast walked for a min and did another 2.5min to complete. Last night I did W3R2 and managed the whole thing without changing anything. I am doing these on my treadmill now as prefer to be away from anyone whilst training. This also allows me to do a bit extra at the end of each session, a bit of fast incline walking, etc.