Just a quick update to say that I got through W7R1 this evening.
I struggled throughout, but ran it slowly and managed to speed up at the end. The only reason I didn't quit is because I am a stubborn old so-and-so and I don't like to fail at anything. I had to have a nap on the sofa when I'd finished!
I think the reason it was so tough is because I made the mistake of attempting a long run when I was hungry. I'll will learn from that and make sure I have some fuel on board for the next one.