We recently bought a £3k Mitsubishi Outlander and very impressed so far (diesel so not sure what petrol are like). I'm 6'3" and plenty of room in front, lots in the rear as well, not a bad drive for a 7 seater and even the wife likes driving it..
probably not the most room in the back for the money but the mk2 octavia estate is surprisingly good. We have it for our family bus and I am 6ft5 and adults can sit behind me whilst driving.
The superb is a different league in terms of space but as you say out of budget.