I use Vetmedsplus and they are excellent. They supply the drug I want at the lowest price. But they won't be the cheapest for all drugs so shop around before you order.
http://www.vet-medic.com/
i get my cushings meds on there, much cheaper than all the others..
i also get the cats and dogs flea and worm treatments on there, cheaper...
Have you managed now Fat Piggy? I just got onto it - maybe it was just a blip.
I ended up going with Pet Dispensary as it was quite a bit cheaper for the medicine I was wanting. In hindsight I will request I pay for the signed delivery as it took almost 2 weeks to get to me!
Just been in the site- great. Prascend at 85p a tablet and free postage so I shall be asking my vet for a prescription next week. Every penny saved helps!