After 3 disappointing runs and posting on this forum, today I set out again and followed your advice. I did not push myself on speed. I ran for 30 minutes at my “Laura” speed, and at the end I still had some puff left in me, so I ran another 5 minutes as fast as I could, safe in the knowledge that I could then slow to a walk to cool down!
Thanks for your words of encouragement. I will now focus on consolidation