Ilooklikemrsploppy - I don't know how a cafe or restaurant would successfully screen off an area of their outside space, so that the cigarette smoke won't drift into a non-smoking area, and most don't have two completely seperate areas (a courtyard at the front of the building and a garden at the back, for example), and I can't see how else they are supposed to create two completely separate areas.
The solution, as a previous poster has said, is for cafes to decide to become completely non-smoking, inside and out, but they will then lose some custom from smokers - so it will be a commercial decision.
I am old enough to remember the days when there were designated smoking areas inside restaurants - and they never worked, in my experience. I always hated the smell of cigarette smoke from other areas of the restaurant or cafe, when I was eating my meal, and I am much happier now there is a ban on smoking inside - but as my mum is, and always has been, a heavy smoker, I do appreciate the restrictions placed on smokers, and can understand why they wouldn't want even more - ie. you can't smoke outside our cafe, or you can only smoke in the special area, round the back by the bins!