Well you can buy pretty much any of the Puntos available at the moment on Auto Trader
I don't really look too much at cars for sale now I've got mine, but I would say you might be able to get at the newest a 13 plate 595, maybe a high mileage 14 plate, assuming that's what you're after, and going off the fact my '14 Punto was 10 grand.
There's not really any Abarth that isn't decent, although I suppose that does depend on what you are after. You aren't going to get a 695 with that money I would say, but you can probably get any variant of the 595 for sure, and all the Puntos available (Grande and Evo) are going for less than 7 grand, they're obviously a bit bigger, personally have a better driving position and they normally have a little more grunt than a 595. There is also the exclusivity factor, there are less than 1000 Puntos on UK roads, compared to around 10k 595s and 695s. The tradeoff with that is that there is less stuff available to do with the Puntos when it comes to mods, and it is a bit more work too, whereas there are more modded 500s than you can shake a stick at.
Hope you do find a belter of a car, and welcome to the AOC!