... as usual, Lewis. I do have to take issue with one point on the first page, though. I understood, from reading the local press, that the problem in this part of the world isn't so much the Singapore Strait, but the Malacca Straits, between Peninsula Malaysia and Sumatra. That would also better match your requirements for a nearby lawless or poor area sheltering them: Johor Baru and Singapore are reasonably provided for, or at least the part of JB that's at the very bottom of Malaysia. It's also an incredibly crowded shipping lane where people have to look out for each other, since the consequences of doing otherwise would be disastrous.
The Malacca Straits, on the other hand, are much bigger, although also very busy. That said, Sumatra is a *very* large island, with lots of places for bad guys to slip away. Also, the Indonesian government seems to take the problem less seriously than the Malaysian government. They have far fewer resources in the area than Malaysia, despite Sumatra being larger than Peninsula Malaysia.
As for a Naval solution, would it not be possible for someone at Thorneycroft or the like to design a new version of an MTB? They seemed to have some success against E-boats a number of years ago, I recall - fast, nippy and with some serious teeth. Perhaps acting as a minor battle group with a helicopter carrier?
Finally, while piracy on the High Seas is still an offence liable to summary capital punishment on the statute books, I believe it ranks alongside arson in Her Majesty's dockyards as an anachronism. Furthermore, I think there just might be some pushback against from other nations, who might decide that RN ships were indulging in piracy every time they were enforcing arms embargoes or the like.
Helicopters - would the need to be of the black kind? Not going for the obvious because, in this part of the world, it ain't no joke.