Someone helpfully told me to time it so that I breathe in on my right foot down ad=nd breathe out on my left foot down (obviously, not consecutive steps). I also find it helps to step down from a kerb on my left and up to the kerb with the right. It's all about stretching the diaphragm on the right side apparently.
How is everyone getting on? I've just finished week 5 and despite thinking I wouldn't be able to do day 3, I actually found it easier than day 2. I think I found my rhythm towards the end. And when the voice said "You are half way" I thought, wow, that was 10 minutes already?!? 5km seems achieveable now