I managed to complete W5R3 today ... woohoo! I took it nice and slowly but had to silence the little voice in my ear telling me that I didn't have to do this! I started a new route for W5R2 and today which is more road running and more hilly. I found that running downhill on the hard surface gave me sacroiliac joint pain which I haven't had before. I am running in some rather old trail running shoes that I previously used for dog walking. I'm going on holiday for two and half weeks next week and have promised myself that if ... no, when... I continue with C25K when I get back I will book myself in for gait analysis and buy some proper shoes which hopefully will help.
I hope to be able to do a couple more runs before I go away but it'll be too hot to run when I am on holiday, so I'm thinking I might repeat W5 when I get back.