The AC world is a crazy one, I've honestly yet to have any real trouble attaining anything but every day the threads fill with posters frustrated at scalpers or the lack of availability. I bet Bandai does this on purpose.
Its a very hit or miss thing (right now the prices are extortionate) but in the 2-3 weeks I've been picking up AC figures I've seen them cheaper there than I have at Mandarake. Take that as you will
If you're ever in the market for getting more of the AC figures I highly suggest frequenting Amazon UK marketplace - I've managed to get both Zangetsu and Baron for retail price there despite their huge Japanese aftermarket prices.
Dunno how interested you are, but I thought it worth sharing to a fellow UK-er!