So I was following the plan until the end of week 6, where I hit a wall. So I thought, OK, step away from the plan and work up to the 25 minutes non-stop, then you can carry on.
I mention this, because if anybody else is finding that they are hitting walls, my approach seems to be working well. I managed 15 minutes non-stop today, after building up slowly from 10 minutes for a few weeks.
I hope to get back onto the plan and finish those final 3 weeks soon. But for now I feel accomplished.