Okay, here's my thinking. The Straits Settlements were a few outposts or colonies along the Straits of Malacca - a heavily used transportation path. I think all of the Settlements are now Malaysia. Thus, going with Malaysia in particular, I'm taking us to the Philippines. Good? One Philippine piso, 2003.
Sri Lanka, actually Ceylon at this time, with this 1921 50-cent piece. I think the mint mark, a B, is the Bombay Mint, which, of course, is the Mumbai Mint today.
Meaning no offense, I am thinking Drabchi mint. Please see: https://www.zeno.ru/showphoto.php?photo=193832
I got a 1923 a few days ago and have no idea how to tell what mint it came from. I bought a AR rupee that turned out to be AE falus. Sellers often do not know what they are selling. Also got a VOC from occupied Pondicherry which was totally mis labeled.
This seller is generally good. I had a communication going with him on a silver Bhutan half rupee that did not match the KM or Numista listings for silver, but he was correct. I don't see any clear help in KM for the Tibet mint marks and Numista just lists it as "type b".