Yes, I too get eye strain for the first week or two when I reduce my prescription. If that happens I just put on my stronger prescription. But soon I'm used to the new one. Before when my vision was getting weaker and weaker and my prescription stronger and stronger I noticed eye strain and headaches with the new prescription. The doctors always say, "you'll get used to it". That's true but if you don't maybe you got a prescription too weak/strong for your current situation.
I'm sure there must be online prescription glass companies in the EU. May have to search a bit. If not join those yahoo groups and ask around there. There are people from all over the world on those groups. And I highly recommend those yahoo groups. A great online community of people commited to improving vision. I think curezone is great but it's just not quite there yet for vision improvement. I came here for cleansing advice and stumbled upon this vision forum. :)
As far as astigmatism. If it's not too bad you don't have to have it. After all there are so many people with astigmatic vision and they wear contacts which do not correct for astigmatism. I noticed that as I practice good vision habits my astigmatism changes. My last doctor noticed it too while I was taking the tests. I'd recommend leaving the astigmatism out and if necessary up the prescription slightly to compensate for the lack of astigmatism correction. But that's my experience. Your body is different and may or may not be ready for it.