Cheapest 16660 in Chrono24.com is 7200 dollars.
https://www.chrono24.com/rolex/seadw...-id9722538.htm
The most expensive is almost 30.000 dollars.
https://www.chrono24.com/rolex/1983-...-id9687661.htm
With paperwork they all seem to be over 10.000 dollars (8700 pounds) in Chrono24.
Both 16660 and 16600 prices have gone up recently. Not as much as 16710 but they're not getting any cheaper I'm afraid.