So the sandbox was in fact, here:
A pretty basic set up of a fake beach and a few concrete seawater tanks. Fairly standard operation mirroring others around the world: locals get paid for eggs so instead of eating them they bring them here carefully, eggs go in artificial nest in fake beach protected from predation, baby turtles hatch, baby turtles go in sea. Hatch rate/hatchling survival is increased, hopefully turtle numbers increase. I don't know how well this works from a practical perspective (and I'm unaware of but I'd love to hear of any research on this) but the guy said they'd released something along the lines of a quarter million turtles. Which sounds like something which would help populations.
If the writing on the sounds is too small for you to read I can tell you that the signs simply note type of turtle number of eggs and date of laying. "Nests" of all 5 Sri Lankan species are in the beach. Guttingly a leatherback nest was showing signs of hatching and I think if we'd been a few hours later I'd have finally photographed my nemesis turtle albeit in non-wild conditions. They also have captive specimens of the other 4 species for rehab/education. and I'll show some shots of those at some point.
For Olive Ridleys and Loggerheads, hatchlings are afforded "special treatment". Apparently the Olive Ridleys are held back a little due to their small size and softness of shell on first hatching. After a week in a tank they harden up a bit and are released which meant I got to see some hatchlings.
Immediately before taking the shot below I was trying to get video of this cool trick I saw someone do at a turtle hatchery on the bbc's "Last Chance to See". Apparently if you hold a baby turtle out of the water by bottom of its shell it thinks it's on land and so will "crawl" by rotating first one front flipper then the other. Hold it by the sides of its shell and it'll assume its in water as it feels weightless and will try to swim moving both flippers together and even lifting its head for little breaths. This little dude just looked at me like "dude, whaddaya want me to do?" and then refused to move at all.
"Seriously dude, what?"
Loggerheads are the rarest of Sri Lanka's turtles apparently so their hatchlings are also retained for a while to harden off and then released.