This is the reply I received from Wyre Forest CCG (in north Worcestershire) as I am about to move to a new area.
"Good morning .............The Medicines Commissioning team have asked us to reply to you as follows, which we trust is helpful and answers your query regarding the prescribing of Liothyronine.
The CCG is currently reviewing and updating its position statement on the prescribing of Liothyronine in line with the NHS England guidance on items which should not routinely be prescribed in primary care. The guidance supports the use of Liothyronine on the recommendation of an NHS endocrinologist in specific circumstances. As a new patient you will need to discuss your medication with the new GP who will be able to assess whether you meet these criteria.
Kind regards Medicines Commissioning Team
NHS South Worcestershire Clinical Commissioning Group
NHS Redditch & Bromsgrove CCG and NHS Wyre Forest CCG "
I guess I should be grateful it's not a downright No.