Just listening to this interview with Professor Håkan Alfredson, it's quite interesting and discusses the difference between midpoint and insertional tendinopathy:

https://soundcloud.com/bmjpodcasts/t...dinopathy-with

An important point to note is that if the tendinopathy is insertional that the heel drops should only be performed to the point where the foot is level and doesn't extend beyond the pinch point.

I've been doing these exercises on the leg that is showing symptoms but you have me thinking that I should probably do them on my other leg too.

For what it's worth I don't find the 2 x 90 repetitions each day to be a problem, it takes a little time and I am getting muscle soreness towards the end of the sets, which I take to be a good thing. I don't think it will be long before I start loading.

I think you are probably very wise to do these as a preventative measure Mike T