As Worzel said, i'd recommend popping into Park Camera's new shop (its in Burgess Hill). Big place and you can try the different camera bodies to see how they fit your hands/grip etc. Also good to try different lenses, when i was looking at my first DSLR i had no idea what a 70-300mm lens would do, zoom-wise.
Even if you don't buy, it'll help you decide what you want to target on the second hand market
