Decent used piano for less than £500?

[itm]

I've been learning for about a year, and until recently only owned a Yamaha DX27 synthesiser. While a decent instrument, I now want something that feels like an acoustic piano (but with the convenience of an electric instrument).

I recently acquired (for free) a Yamaha Clavinova CLP-350. While it sounds and feels great, it is in a poor state of repair (sticky keys and other keys which randomly sound out much louder), and I suspect that it may be beyond economic repair.

I'd like to buy a used instrument but I don't have a huge budget - could possibly stretch to £500 but would really prefer to spend £250-300. Am I likely to find anything worthwhile? If so, can anyone recommend any specific makes/models?