3rd time out of c25k and followed the recommendations I've received on here to go slowly. I didn't actually speed up from brisk walk really, but changed gait to jog albeit feeling just about like jogging on the spot! The run sections felt so much more achievable; all I have to do now is find a way to manage the exuberance of the younger dog wanting to pull my arm off and get him to try to go at my speed, not vice versa!
Feel much more hopeful about moving to 2nd week run now, where I was very worried about how tough it was feeling to do the running parts.
So thanks for the advice. Updating here to affirm experiences of others regarding the expectations we put on ourselves; brain was telling me to click into previous run speeds (which were slow anyway) but body physically couldn't do it. One little torturous problem solved