Reflecting on the comments I wonder if the origin of the problem was down to the heating element in the Electrim mash bin, which looks like a simple kettle type element. The strike temp was about 75, however I left the mash bin on the lowest setting, but I guess the element would have still been creating substantial energy, and possibly have some of the grist sitting on it!. For the second batch I made yesterday, I turned the electric off once strike temp was right, mashed and covered for 1 hour, temp stayed between 66 -62c throughout the mash. The first noticeable difference is that the wort smells much more intense, and a whole lot sweeter. I left it to cool overnight, pitched the yeast at 22-23 c this morning and fermentation is underway. I think this time I'll not bother moving to 2nd FV until fermentation and dry hopping have been done. Summary, feeling a little more confident. First batch has stopped again, so I think it might now be added to my compost heat, it needs a little drink anyway 
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