Who told you that astigmatism wasn't allowed? I have astigmatism and I hold a JAA Class 1 medical. I am also cross eyed and mildly short sighted. I have to wear specs to fly. The main thing is can your astigmatism be corrected with spectacles?
If you are really concerned, speak to the CAA medical branch directly. They're the ones that say yay or nay, no one else. I believe if you think you may miss out, you can do the eye test first and they won't charge you the full fee for the medical.
You could print out the JAA requirements and see if they match up, or ask the optician to test specifically for the items.
Australia's eye standards are much more reasonable. Just ask any one who's colour blind.
Second thoughts, just speak to the CAA's medical branch. Tell them your script and they should be able to advise you.