Sri Lanka
I would put Ceylon tea on the list for Sri Lanka because it is the kind of thing that feels useful once you are home, not just another airport purchase. It is a good one because people can try it slowly at home, and it makes a nicer gift than a mug with a place name printed on it. The reason it works is that it gives you a quick reminder of the trip without needing to keep a fragile ornament safe forever.
Sri Lanka
This is exactly the sort of thing I like bringing back from Sri Lanka: small enough to fit in a bag, but specific enough to remind you where you bought it. The best version is usually the sealed jar, tin or packet from a normal supermarket, spice stall or food hall, not the most expensive tourist version. It is also the kind of thing you can talk about when someone asks what you brought back, because there is usually a little story attached to where you found it.
Sri Lanka
Batik sarong is worth adding because it feels like something you actually noticed while travelling through Sri Lanka, rather than a generic souvenir. I would avoid the obvious tourist print and look for something with a local pattern, fabric or cut that still works with normal clothes back in the UK. The ideal version is modestly priced, not too bulky, and good enough that you would buy it again even without the holiday memory.
Sri Lanka
True cinnamon sticks with delicate sweet flavour; prized for baking and tea.
Sri Lanka
When I think of an easy, crowd-pleasing thing to bring back from Sri Lanka, coconut sambol mix is a good pick because it does not need much explanation when you hand it over. The best version is usually the sealed jar, tin or packet from a normal supermarket, spice stall or food hall, not the most expensive tourist version. I would rate it higher when it is locally made, clearly labelled and easy to use at home, and lower when it is just tourist packaging.