Hi Phil,
I agree that your
dha knife is a nice old one from mid-to late-19th C. The silver covered scabbard is typical Shan work, with a flat toe, filigree bands that segment the presentation and filigree wire work in these segmented panels.
Knives such as these were often decorative or status symbols, and Shan men wore them as part of their attire when they got married. As a result, they are fairly common. Your example is better than average with a nice intact ivory hilt.
Not only the blade needs a clean. You should give the filigree work a bit of gentle cleaning to remove some of the old polishing compound. A soft tooth brush, some warm soapy water, and patience are needed--the filigree work can be delicate and a bit fragile, so take it slow and easy.
Very nice knife for a flea market pick up. You will see online what selling prices are being asked for these knives now. I suspect you got a good deal at the flea market