This morning I did w2d1. I was able to do all the running intervals albeit at my "not very fast" pace. It hurt my knees. I was 1 minute slower around my circuit than w1d3. Maybe because I wasn't able walk as fast as I usually do, in my walking intervals. But I got round - that's the important part.
After an hour or so I felt quite recovered and knees had stopped hurting and I felt like I need a good long walk to get rid of the kinks. 2 hours and just over 5 miles. Very tired for the last mile, but otherwise a really enjoyable walk along the river and along trails.
The trainers are new, so I'm sure they're a big factor in the hurting bits because they're not very supple. I felt some tension across the top of my foot the first couple of times I wore them before I ran in them. I expect things will improve when they're worn in a bit more. I might try using my old trainers on the next run day and see if that helps. They're very old with holes in the insoles though, so I'm worried they will rub the bottom of my feet sore.
I've decided the sore knees are actually sore just below the knee, to the insides of the legs rather than the outside and not the knee joint itself so I'm not feeling quite so concerned about that now. My legs feel OK tonight. perhaps a little tired and achy, but not uncomfortable.