Sony sensors used in some high end Nikons, so shouldn't be discounted.
Is video important to you? If not, you could go back a generation and up a grade, for better build quality and same or better image quality.
Ignore megapixel counts, unless you want to print bigger than A3 in the near future. 6MP is plenty.
This is a little over budget, but would be very tempting. Lens alone worth well over £400…
http://cgi.ebay.co.uk/Nikon-D80-Digital-Camera-with-18-200mm-VR-Lens-MINT_W0QQitemZ300368119193QQcmdZViewItemQQptZUK_CamerasPhoto_DigitalCameras_DigitalCameras_JN?hash=item45ef55c599
The D80 with the 18-70 kit lens will leave you change from your budget for a 70-300mm tele zoom and some accessories.
If you want video, then go for the latest model, as the earlier video capable DSLR's had manual focus video only, and any cheap proper video camera will easily out perform it.
Also consider Samsung cameras, they are rebadget Pentax cameras and usually a good bit cheaper.