Thanks for all of your input
I can see how seasonal dietry changes could easily upset the mechanism.
I can't really attribute this to me though due to being on such a limited diet already and eating the same few things all year round.
The only different thing I can think of is I recently tried adding the odd apple to my diet. Fruit wise I only eat banana's and I fancied trying a bit of variety. But I only had 2 over the course of a week & peeled. I klearnt yuears ago not to ever eat apples with their skin on! Surely they won't still be wreaking havoc on me though