Seeking the return of my enthusiasm, I went along to my local running club this evening. Loads of people including some I know from other places. I joined the one up from the beginners and we were definitely put through our paces. 4 sets of 400 meters - 4 sets of 100 - 4 sets of 400; the aim being to keep the times the same on the similar distances but do the middle set faster. Good to have someone there with a stop watch and a friendly structure to the evening. The programme changes each time to focus on different things. As great a mix of people as in this forum but I was pleased to find myself ahead of longer term runners.
It was perfect for me - I really wanted to skip the last run but persuaded myself to do it and completed the whole thing - so just that little push beyond what I wanted to do.
I will only be able to go fortnightly because of other commitments so plenty of time for full 30 minute runs in between to keep up the stamina.