Iodized salt can be found there ...
Finger length ratio: Some of your descriptions made me curious. This does shed a little light on the situation. This probably has some bearing on your condition, but not know how.
You can eval your overall thyroid function by checking oral body temperatures as per the thyroid basics sticky. Thyroid hormone fT3 is part of your body's temperature control loop and feeling cold may be a strong clue. UK has iodine in milk, less so if organic, but that is not guaranteeing enough.
Would be good to test freeT3 if possible, but if body temps are good, may be no need.
Total T is what you are probably going to get, free testosterone is important too.
Those labs will be a good start.
If LH/FSH are lowish and T as well, then you should test estradiol and prolactin to see if they are causes.
There are several variations in that basket. Something that could be tested for. There may be other possibilities.
In considering such types of things I am wondering if your HPTA can be set right or if you will need TRT. TRT would complete your virilization. So you would then focus on reading the protocol for injection sticky to see what you need. NHS is a completely different reality. You would want to have your sperm analysed. If fertile, you need to fight to perserve that, otherwise not.