Being in the UK means that predominantly you will only be tested for TSH. TSH is a pituitary hormone that is affected by so many things that it is totally inadequate as the sole diagnostic for thyroid status. UK doctors will tell you that TSH accurately reflects levels of the actual thyroid hormones; however it cannot be shown that TSH correlates well with either of the biologically active thyroid hormones, Free T3 or Free T4, much less with symptoms, which should be the most important consideration.
A good thyroid doctor will treat a hypo patient clinically by testing and adjusting Free T3 and Free T4 as necessary to relieve symptoms, without being constrained by resultant TSH levels. You can get some good insight into clinical treatment from this letter written by a good thyroid doctor for patients that he sometimes consults with after initial tests and evaluation. The letter is then sent to the participating doctor of the patient to help guide treatment. In the letter, please note the statement, "the ultimate
criterion for dose adjustment must always be the clinical response of the patient."
I can give you all kinds of additional links to scientific studies that further support clinical treatment, rather than using TSH. Whether or not you can persuade your doctor to adequately test and treat you is the key question. A fellow UK member who was finally successful in getting adequate testing and treatment told us this, "What I have learned from my experience is that you have to go to the Dr's office and TELL THEM WHAT YOU WANT and to go backed up with knowledge. You have to tell them that you have done your reading and looked into your condition and care about the long-term treatment of your health and thyroid. If you fight for what you want, you will eventually find someone that is happy to go along with your wishes. But we all have to take charge of our own health, right?"
If you want to give that a try, I suggest tests for Free T3, Free T4, the thyroid antibodies tests (TPO ab and TG ab), Vitamin D, Vitamin B12 and ferritin. If unsuccessful with that then the alternative is to go private. If you want to try that, I have the names of several doctors in the London area that were recommended by fellow UK members.