1st one over and done with, I found it slightly easier than W4 - the first walking gap in week 4 is almost completely flat on my route, and the two runs around it on hills, so today the first 5 mins were hill then flat, and I got to walk up the second hill for a bit.
I think I also experienced a proper runners high at the end, I was a bit disappointed it had to end.
Also, another milestone was dropping to 13st 5lb in weight in this morning, my lowest weight since I was in my mid twenties (from 16st 12lb in July 2019), especially satisfying as I am a lot more muscular than back then (relatively - I'm no Arnie!)