I think, if they go to New Zealand, it should be a two-parter. Hell, have Peter Jackson pick out locations to shoot in and write the episode around that (New Zealand is a cool-looking place). I'm sure it'll be fun. He'll probably get paid in usable currency in addition to that Dalek, though.
Of course, schedules would have to coincide and, given Doctor Who's tendency to struggle at setting a schedule, that could be difficult.