uffington sb:-
They want to return to Ile Boddam, where the village of Chagos was. They do not want to go to Diego Garcia.
Do you have a link for that assertion? I ask because Diego Garcia is by far the largest island in the archipelago and was presumably home to a fair number of inhabitants. It might be that their leaders have conceded that they accept a return to that island will not be possible while the base is there. That is quite different to saying that they don't want to go to Diego Garcia when it is possible.
Here is the Beeb summary of the situation after the lost Supreme Court appeal in 2016:-
https://www.bbc.co.uk/news/uk-36659976