After deliberating, I decided to contact Retfords again about Mini. They were lovely, as always, and very helpful. It is more than likely that Mini has a cyst behind her eye. In order to fix this problem, it is very likely that the eye would have to be removed. The cost for this surgery is in the region of two hundred pounds. It is also not certain that she would survive the anaesthetic. All in all, the worst news possible.
So, I asked the lovely vet what would happen if I simply left Mini, stopped messing with the eye altogether, and just kept her well fed and watered. The answer is that the eye will shrivel up and heal over, although this may take several months. However, she will live.
So, as I see it, I have two options. Risk Mini's life on the operating table, and pay several hundred pounds more towards treatment, or leave her be. Either way, she loses the eye. One way, she may die because of a quick fix. The other way, she may be in pain (although the vet can't be sure) for some time.
Rock and a hard place anyone?