It's a beautiful sword Alex. I find that the unusual etching is maddeningly familiar, expecially the distinctive elephant head.
I echo Nando and Jims suprise that nobody else has come in on this one.
Tremendous (as usual) deductive reasoning from our own Mr McDougall.
It may be that you'll have to try a specialist group for the Napoleonic wars/era or as Jim suggests slightly later into the Victorian era.
Best
Gene
Edit: I was going to PM you a suggestion but your account doesn't accept private messages. Hopefully it's ok for me to suggest it here instead?
I can only think of one Napoleonic specific forum that might be helpful:
www.napoleonicwarsforum.com
Make sure you stick around here to show us the rest of your collection. If this first one is anything to go by, you have a good eye for swords!