I have the 4.5" backspacing mods with around 33" tyres and a gwyn lewis kit and no rubbing what so ever. Although they have an extra 1.5" added to the width on the outside with the beadlocks. Oh, and they are fitted to a classic with a 70mm lift. This should mean on your defender, they should also not rub as your tyres will be around 33" tall. Although this will depend on what suspension setup you run obviously.
Also, I paid about £32 per wheel I think from mansfield motors here in east anglia.