DSLR vs others
If the 650D for £549 comes with a lens it won't be one suitable for wildlife photography. Even second hand you are looking at £1,000+ for camera and wildlife lens. For £400-500 you can get either a very good compact camera with fixed lens (bridge/superzoom) or a DSLR with a basic lens NOT a full DSLR set-up
If I were you I'd go to a camera shop, have a look at the options and have a chat to someone.
We can begin saying, and im sure every1 agrees, photography is an expensive hobby no matter how you look it or what genre you intend to shoot, fullstop. Second, this is a bird forum, not a nature photography forum, so we thinking birds first, other wildlife second, hence the basis for my opinion. Thirdly, the original post by
Plentiful specifically requests and I quote, "
Which one would you recommend so that I can add a lens at a later date?" This, rules out a bridge camera. Ultimately, to buy and build on a system, you have to spend, no matter how much one wants to stretch that penny. I dont agree with the save today, spend more tomorrow philosophy cause one will eventually find the limitations with a bridge camera it will end up being expensive if you decide to upgrade. Having said that, im not trying to downgrade bridge-camera capabilities at all, as it is possible to produce excellent bird photos with them as one can see for themselves on these forums.
But there are serious limitations to consider (fixed lens, minimum shutter speed for long exposures and maximum shutter speeds for freezing action in bright light) much less so with Rebel/xxxD type camera which can provide a longer shelf life than a bridge camera. Besides, by having a decent DSLR body, one can hire and tap into a vast array of professional Canon lenses at very affordable prices, which will in turn enable you get a feel for those lenses and save up for the lens you prefer after having used it for some time.
I purchased a rebel T4i/650D in the US for £450 including delivery, camera bag and EF18-55lens (good for landscapes) making use of a special offer. You can prob now get it cheaper than that body only, and if frankly, one thinks that is expensive, considering the costs of wildlife photography, then there not much else I can say. On the long run, a good solid DSLR will prove its worth and end up being a sensible purchase.