Like SG says, I did the same parkrun as he did. 19:27 official time so the last 3 outings over the distance have been 19.2x so seem to have reached a plateau. Need to decide if I am happy at that level or need to do some serious work to get it down to 19 dead. Trouble is I have a busy summer ahead and it is probably a sensible plan to enjoy the summer and take the running a bit easier and then try for another cycle in the late summer / early autumn when it is a bit cooler and yet the surfaces are still hard, dry and fast.
SG: good solo run there, you now need a real race with a few people round you. Marlow 5k July 5th and Datchet 5k July 12th.
I have to agree that heptathletes and high jumpers provide a good pool and of course, as they follow a normal distribution, there are exceptional highlights such as Blanka and Klüft, but my analysis offers the result that pole vaulters win on average.