I'm not so sure it's a matter of post code. Rather one of condition and the proven ability to improve control with Libre.
I was fortunate to be able to demonstrate an improved level of control. I had been self funding for a few months, an was able to show that my incidents of hypos, an to an extent, hypers, was improved when using Libre. I've now had two prescriptions fulfilled and don't forsee any immediate change to that.
I also have a very specific requirement due to another medical condition which resulted in major surgery to my gastro track early this year. I won't bore you with the details but it is documented here. You wouldn't want to swap!
With normal (?) diabetes I'd suggest not relying on your GP or consultant writing a case for you, but have a documented argument that it improves your situation.
YMMV