Thanks KSman, I've taken your advice and got some selenium tablets. I've also got bought some decent multi vits and Vitamin D. Hopefully they will help.
Unfortunately, I went to see the specialist, who essentially dismissed most of the symptoms I mentioned (tiredness, foggy-headedness, feeling cold, lower sex drive, poor sleep etc.) and said that i just need to exercise more and eat less.
He didn't enquire as to how many calories I consume, or really asked what my diet is like. As soon as I said that I used to lift weights more regularly than at present and used to weigh over 230lbs at one point, he clearly had made up his mind that I am eating 4,000 calories a day, or something. Very disappointing.
When I talked about my symptoms, especially feeling tired and poor sleep, which is one of the worse things for me, he simply dismissed that and said that because I am 'successful' (debatable) and in a profession, I would not be able to perform well in my job if that was the case.
I suspect he thought I was just trying to get on TRT. In fact he said 'some doctors would put you on TRT, but I won't'. Then went to talk about how it is linked to infertility and I'd never be able to stop taking it etc.
All in all, I'm feeling very bummed-out about this, as my GP had pretty much told me that I would be prescribed some medication to help with my Hashimoto's and the symptoms associated with it. The only good thing I can about the specialist is that he requested further blood tests to check my pituary profile... oh, and he has also referred me to a clinic which will teach me how to eat properly!
I think on the NHS we can request a 'second opinion'. In this instance I will most definitely be doing that.
Thanks once again.