So, I graduated and kept running but didn't improve. The effects of the radiotherapy were very debilitating to my energy and breathing. Could run for 30 mins but at about 5K per hour. I walk faster than that under normal circumstances! Found myself giving up.
So, I've started again, trying to go a bit faster in the runs i.e. making them more run-like than plodding, esp. in the last minute of each bit. Currently in wk 4 and as someone has written elsewhere, that first 5 min run almost caused a refusal! But the achievement is wonderful. And the mornings are beautiful.