Speakers have developed a lot in ten years. You'll be better off with something new.
In that budget, I'd be looking at a pair of Q150s if you think you're keen on the KEF house sound.
https://www.accessories4less.com/mak...air-new/1.html
This is providing you can also budget for some stands. In a space that size, I'm not sure if you'll really benefit from a pair of floorstanders over bookshelf speakers. The dynamics of a bookshelf speakers are usually tuned for lower volumes, which could help in your case. Our living room/kitchen area is about 700sq ft and my B&W 607s really fill the room and they're a very small cabinet.