Not sure about availability in Greece, but for £1000 you're most likely looking at brands like Zeller and Stentor if you're buying new. These are generally pretty solid (I've heard good things about the Stentors, although I haven't been able to try one). Your best bet, if possible, is to play as many as you can. Are there any shops near you that sell them?
The main thing to look out for when buying is cracks in the body and the positioning of the bridge.
edit- re: 3/4 vs 4/4, the vast majority of players use a 3/4, although the lines are pretty blurry so you get large 3/4s which are the same size as a smallish 4/4. If you can try before you buy, go with whatever's comfortable but if you're buying blind I'd get a 3/4, especially if you're a DB beginner.