Hi Dom,
I hope I can be the one to help you a little this time

.
On this link you can see a mark a bit like it
http://www.vikingsword.com/vb/showth...ghlight=Tulwar
I too have a sword with part of the mark - see attached. I believe mine to be Deccani - no not Tipu, 18th century.
All the best
Jens
Ps. My blade is very heavy, not wootz and definately Indian made. I don't, yet, know what the mark means/symbolizes, but hope to 'meet' it in other connections.