You can't go wrong with Miyazaki movies, even paying full retail prices for them. Six Quid falls into the category of "purchase on impulse". Porco Rosso is worth it for just the animation of the planes. The dub is a good one, done by for rizzle actors, and not out-of-work Hollywood B-list and Cam Clarke.
I've seen one cutaway drawing of Vanvlak's tank model from one of Miyazaki's art books. It was a hoot. Think of the tank as something more like a navy gunboat (hence the galley cook and Captain's waiter) and you get the feel for it. So much fun...
Curse our perfidiously weak dollar! Five years ago that tank would have been $20. :x