Just to update from my posts earlier. My GP was great this morning. Despite my TSH levels having fallen from 4.7 to 1.2 in the 7 weeks I've been taking levo, she listened to my symptoms and doubled my thyroxine from 50 to 100 mcg! She said, in her experience, it is best to get the TSH level of people with hypothyroidism right at the low end of the range, almost "over treating" it until they feel better. Wow! I was all ready for a fight and it didn't materialise.
Hoping this increased dose will have an impact. Thanks everyone for your advice so far.