If you search back in the Google newgroup archives you'll find I've made comments on this front a couple of times before. When we refurbished our kitchen we started out wanting a range cooker but after much hunting around and looking at cookers we decided that there simply aren't any range cookers (at any price) that really offered what we wanted:- Gas hob Burner/plate good for simmering Fast grill (not a folded immersion heater type) One large and one small oven.
We've ended up buying separate hob and oven(s) and are very happy that we've made the right choice. Even the expensive range cookers (like Falcon, Britannia, etc.) don't offer fast grills or slow cooking plates or even ovens that take advantage of the size of to cooker. We also didn't think that the expensive ones really seemed much better quality than the cheap ones.