I completed week 2 without significant issues but had a niggle at the back of my mind that I should re-do it, as I wasn't feeling 100% mentally.
So glad I have done, because it's given me time to recover from each interval better/quicker and I also took the time to watch the slow running video and put it into practise. This has changed my style a bit - my existing tortoise pace now feels and looks intentional! I have also learnt that my aches and pains during the jog are unpredictable, it could be my right ankle during one interval and my left knee on the next but the important thing is that they only last for the interval and I don't have aches and pains after the session - now!
I've become more familiar with the field that I use, so expecting the highs and lows of the ground have helped me focus more on the actual pace and jog itself. I've also sussed out the music I like (for now) and that Michael's voice works better for me.
So, lots of learning done just by simply re-doing a week.