Link to the sydney Morning Herald that gives an explanation on how the British might have handled the situation better. I won’t even go into the embarrassing circus that followed the British capture.
http://www.smh.com.au/news/world/aussies-repel-iran-navy/2007/06/22/1182019309654.html
I’ve got a slightly different take on it. The attempt on Aussie personnel happened prior to the Brittains. The Iranians were able to test the response and determine the absolute most vulnerable moment for foreign troops, right as they’re leaving the vessel. They then timed the next attempt, against the Brittish troops, to take better advantage of this. What’s startling, and the article mentions this, is why there doesn’t seem to have been any exchange of intelligence between Australian and British troops to learn lessons from the original incident.