I was fortunate to find this example for sale on an Arms Dealer's site.
"... INDIAN PALACE POLEARM FROM CEYLON (SRI LANKA) circa 1850. 92 inches overall. Thick 1 ½ inch wood shaft. The brass head is 16 ½ inches and beautifully decorated...."
Other than the fact my two examples are 0.5" shorter at 16", the pole diameter is the same as mine. With very similar design and execution.
Well done Jim, Ceylon seems almost certain where these originate
Regards David