Thanks for all the comments. I think you're (all!) right that I'm probably not cropping enough - a fault of the the "the wider the better" school of panoramas thinking!
For those that are interested:
West Coast Beach
Location: Gillespie's Beach, South Island, New Zealand
Camera: Fuij S7000, 7.8mm (35mm eq), hand-held, ISO200, F8, Aperture Priority
Location: Tetbury, England
Camera: Fuji S7000, 7.8mm (35mm eq), hand-held, ISO200, F4-F4.5, Programme*
Location: South of Punta Arenas, Chile
Camera: Nikon D100, 12-24DX, 24mm (36mm eq), pano head on tripod, F8, Manual
All the stiches were done using 'Panorama Factory' - which I can't recommend highly enough (esp as V4 now exports PS layered files).
Unfortunately I'm not going to be able to pop back to the shipwrecks any time soon (I live in England!). They were at a lunch stop on a tour I was on - I had about 20mins to capture the image, and no choice around time of day etc. I'm pretty pleased with the result considering...
* This was probably not intentional, but I was rushing to capture the sunset before it went ;-)