OK, i finally found time to go to Cardiff and get a gait analysis and a good pair of running shoes from Run & Become (Brooks GTS18 - I never thought I would spend that much on shoes) . I know i should have done this sooner, to save the knees, but - busy, busy, busy!
Still, knees are improving now (or I couldn't really have done the gait analysis) and as soon as I feel ready for the next attempt at W9R1 I know i am better equipped.