This question
made me think of a story whose title (and much else about it) I can't remember.
The setting is the-near-future-when-written and humanoid extraterrestrials had contacted and landed on Earth. They had been granted a large island in the Pacific to live on - I thought Borneo, but maybe that's wrong, and hence my trouble in finding it.
The protagonist is a spy working for an Earth nation who was dropped off on the island. I can remember nothing about the plot except that he may have been working against other Earth nations to gain technological advantages from the ETs rather than against the ETs directly.
The story was long-ish, probably a novella or novelette, really too long to hold my attention at the time. I read it in an anthology, probably paperback, in the late 1970s.
ISTR the title was short and maybe just the name of the island. You'd think that would make it easy to find, so I may be wrong on that.
ISTR it was by a British author - I thought Ballard, Aldiss, Harrison, or Brunner, but looking through isfdb.org turned up nothing. I remember thinking at the time it must have been from early in their career since it was very techno-thriller-ish and later the author turned out more sophisticated work.
All or part of these factoids may be mis-remembered, sadly.