After jumping through a few hoops and finding a pharmacist at Boots that was interested in the T3 issue I have a workaround for the Mercury T3 issue.
My endocrinologist put me on T3. It helped. Levothyroxine didn't work for me. The Mercury pharmacy T3 was an improvement, but I was started on 10mcg per day and was moved gradually to 60mcy per day. The cost was extortionate. I was still tired and not losing weight.
My sister in America was on a different drug and getting a good result. I noticed that the Pfizer T3 was less expensive in America. Began to do research on getting an alternate T3 here in the UK.
The change was actually very simple. It requires a hand written prescription for generic levothyroxine at the 25mcg dose. The pharmacist then writes a request to the health board to use the alternate highlighting the cost savings. Once approved you're all set.
I am now on the German T3 from Sandoz. The cost is about €20 for 30 tablets. (There are 5 mcg tablets available as well, if needed). They are larger firmer scored tablets. Easy to break even without a pill cutter. Most importantly I feel better and I'm losing weight. My energy is better and unlike the Mercury tablets this seems to be a more sustained release formula so I no longer have peaks and troughs of energy.
I have been on the Sandoz for 3 months. I have lost a stone and had new blood tests drawn yesterday.
If anyone is interested in this perhaps their pharmacist can talk to mine and get the ball roling. My pharmacist had to assist the GP with writing the prescription in a way that resulted in the Sandoz prescription as via the automated system the GP can only order the Mercury version. It needs to be handwritten each time the prescription is renewed.