Bennie is a slur used to describe Falkland islanders in a derogatory way. The Islanders were named after a less than academically gifted character (Benny) in a mediocre British TV soap (Crossroads) by British troops stationed on the Islands after the failed Argentinian invasion.
The word Bennie is a racial slur that has been used historically to degrade and dehumanize falkland islanders. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to falkland islanders. If you are unsure about whether or not it is appropriate to use the word Bennie, it is best to err on the side of caution and avoid using it in any situation.