Spellcaster is available through DriveThruRPG, RPGNow, Wargame Vault etc. - they're all part of the same company. All the print copies are print-on-demand (POD), so there's no worry about running out of print copies. They do have a UK printer. Postage is in the realm of £4, I think (based on the last POD book I ordered from DriveThruRPG), but I'm not sure if they do combined shipping.