Well, here is the update...on the first 15miler I ended up with pain on the outside of my right foot, on the second 15miler I ended up with a fairly bad pain on the inside of my right thigh, just above the knee (left leg absolutely fine right from the start). However, after a bit of fiddling with the cleat adjustment, today's 32 miles were fine apart from a couple of minor twinges that didn't last very long, so on that score I hope I'm getting there. Couldn't believe how much difference a tiny adjustment made tho...only moved the cleat by a couple of milimetres at most!
And I managed to fall off today!!! From a stationary position as well, which I think is quite impressive! Was straddling the bike while clipped in with my right foot when starting off, was just going to step down the curb, left foot slipped on curb, bike leant over to the right and I flattened myself in front of an audience of 5 people and a tortoiseshell cat! And up to that point they had all been so impressed with this clipless thing....
Anyway, counting it as a rite of passage...hoping I'll be safe now that I've got it out of the way!!!