Well, I'd been getting through the programme not necessarily quite finishing every week within a week, but I hadn't had to repeat anything. Then food poisoning intervened. Have been feeling rubbish for a week, and hadn't run for 9 days. So today I decided to repeat W6R1 rather than moving on. It went OK. I felt very sick in the middle of it and couldn't decide whether that was exertion or my tummy still recovering from last week (probably the latter as I haven't had this problem before). And I managed a sprint finish on the last run, which is usually a good sign.
I think getting back into the programme after a break will be more a mental than physical thing for me, though. Last week broke the routine and I had to force myself to start again today. Have already planned exactly how and when I will do W6R2 on Monday, so hopefully I'll soon be back into the swing of it.