I got mine from my local Asda pharmacy (uptil May this year - then I got them on prescription).
You may have to ring in advance to see if they have any in stock though - whilst mine always had them in stock, I think many don't tend to
Closest Asda pharmacy - although other pharmacies can get them too, Asda tends to be cheapest at around £46 each. Our Asda keeps at least a dozen in stock from what I can see, although I am in the Midlands not quite North!
Hello, call around your local pharmacies because they fulfill prescriptions first. Also if you don’t have a reader, your phone with nfc will do the job.