Amanera is usually closed between Mid Aug - Mid Nov. But agree that it can offer great value during Season of Discovery promotional periods. Unfortunately, doesn't fit OP's timeframe and still much higher than $500/night.
Amanyara is lovely because Turks and Caicos is lovely, but the service really is sub-par and while everyone knows that's a Caribbean thing, it's still tough to wait 45 minutes for a glass of beverage. Also, Serge is gone so there's no GM at the moment.
And Necker Island being something exclusive and maybe "super-luxury" (at least in pricing) only has limited weeks (aka Celebration Weeks) when you can simply book a room vs. the entire island.
For 2018:
20th October for 7 nights
27th October for 7 nights
17th November for 3, 4 or 7 nights
Last edited by BESVISOR; Aug 20, 2018 at 3:23 pm