For the next race will find out more of the ins and outs and race accordingly. As for the guy in front he was not letting me pass even though he was clearly and left in no doubt he was slower than me. But hey, in the scheme of things in this case didn't make any dramatic impact.
Re cramping; mea culpa, I tried a different make of running shoe shortly before the race and they did not suit. Being an old git and a bit fragile I was not 100% in the legs dept. What was the tipping factor was that I wheeled sharp left at a turning and I reckon it was that turning, wrenching motion wot did it so silly boy me
Silly sod, should have known better.