Thank you Nathaniel... and much thanks for posting the link to a similar example.
I've combed through Mark Bowditch's site looking for similar examples, but didn't find anything that was as close a match (stylistically at least) as this one (blade profile aside).
There were quite a few other very interesting items in his estate I either had to pass on or missed out on acquiring (including other items from the Thai royal family), though I was grateful to have the opportunity to acquire this.