I doubt that the lack of "papers of ownership" will be a problem. It is no problem to find an exporter or importer, only what it costs. Agree that you should find a freight consolidation to save bucks. Get in touch with Dig Hadoke as one option. If provable pre-1898, you don't need anything for import, but you still have to deal with UK export.
http://www.vintageguns.co.uk/index.php?option=com_frontpage&Itemid=1