why did british soldiers call falkland islanders bennies in the 80s after the falklands war?

When the British soldiers arrived to liberate the islands, they nicknamed the islanders 'Bennies' after Benny, the simple soul in Crossroads. But this caused so much upset that the soldiers were banned from using the term, and instead nicknamed them 'Still' - as in 'Still a Benny'.

Falkland Islander, after a character in the British soap opera Crossroads.

At the time, wearing a woolen bobble hat was deeply unfashionable in the UK. Falklanders were wearing these hats and the resemblance to 'Benny' was noted.

It wasn't meant as an insult.

My last visit was in Sept 2007 and despite the best efforts of the Command, they're still being nicknamed 'Bennies'.

First answer is correct.

However, I have also heard, that the locals refer to the servicemen as Whennies. From "When I was in the Falklands..."

After the dope in Crossroads

I was there in 94 and we still did then