You enjoying it russ?
450d is the way to go, £400 budget will mean lucky to get a 40d body only, no lens with it
Just to throw a curveball in there:
I have a D80 and I love it, it with a 50mm f/1.8 and 18-55. It's by no means a "starter camera" but it's a lovely bit of kit, if you're lucky you can pick up a 2nd hand D80 body for £250 off the 'bay