Thank you everybody! First of all, my surgeon said that lying down on your front is now thought not to make much difference so he told me not to.
Secondly, the op itself really was nothing to worry about I was terrified! You have numbing eye drops and an injection into the skin around the eye (I hardly felt it) but the great thing is that the staff make a sort of tent over your eyes so you can't see any scary instruments. If anything, it was just a bit boring.
No, it is not to prevent macular degeneration. I had a hole which came from nowhere but the rest of my maculars are healthy. If it hadn't been for a routine eye test at Specsavers I would never have known because your stronger eye can take over for you.
Yes, there are restrictions, you can't fly for 3 months or so or go scuba diving, mountain climbing etc - anything that affects the pressure in the eye. You cannot have a general anaesthetic which contain nitrous oxide (Entonox I think) as PollyDolly said, for 3 months and you have to carry a red alert warning card and wear a yellow warning bracelet.
Nobody should worry about having this op. It's inconvenient but worth it. Thank you MawBe for your encouraging message.