ERFA without prescription

[Valt]

I have been very fortunate in having an endo who prescribes Erfa, which I can get from the hospital pharmacy. However, instead of my usual 3 months supply the pharmacy will only release it in one monthly instalments, involving several phone calls each month to get it 'released' and a longish journey each time. I have been unable to get a definitive answer as to why this has changed but today was told it is due to cost implications and it may not always be available. I am understandably, I think, concerned that this is a step in the wrong direction so have decided to investigate buying online, initially just to ensure I have reserves and also in case of sudden withdrawal of prescription. Would appreciate any information as to where to source it. Many thanks.