I think it’s a foregone conclusion that the Falklanders will overwhelmingly vote to retain their status as a British overseas territory.
Argentina has already denied the legitimacy of the referendum, of course. But they’ve also said they won’t use force to reclaim the islands.
Our current policy of not taking sides is silly. We should just take our lumps diplomatically with Argentina, and declare what everyone knows to be true- the Falklands are British, and Argentina has no claim.