Hi Charles,
That's a great piha, very complete. Based on the quality work it would almost have to have been made by the Pattal Hattara in Kandy (the king's royal workshops). They were not around long after the British took over. I would date it a little older, probably very early 1800's.
That's a beauty, a really good find.
-d
www.pihakaetta.com for some more info.