Last time I was there was '80 or '81; there were a few good spots just north of Trincomalee, some interesting little islands & such. Zero facilities, we'd filled in the Philippines, and when tanks were drained we were done with Sri Lankan diving.
A lot of unpleasantness in the area since then could make it even less of a good prospect today than it was 20 years ago.
Good luck, and please update us when you find out for sure.
-------------
I have a memory of Ceylon (Sri Lanka) that is vivid and worth sharing. When we pulled in there it was after being at sea for 63 days - 63 days of open ocean air. When I woke up as we were approaching our anchorage, my nose was assaulted with the acrid smoke of a thousand dung and coconut husk fires the Sri Lankans were using to cook breakfast. After leaving there, even the ship's laundry (which boils the laundry) took a month to get the smoke smell out of our clothes.
--------------
The "fresh" water was so badly contaminated that those who dared even shower in it came down with rashes and traveller's diarrhea.
--------------
The spices they use in local dishes tasted like perfume to me. I'm a gustatory guy who relishes local cuisine, but even for me this stuff was a bit hard to take. (but I ate it... and smiled)
Rick