Well the punch up was from the first time they experenced a culture shock and when they only saw the miss macross show so that can't really be used as a good example. With the inital debreifing yes there was no military information, but that wasn't what the show wanted to focus on at the time, it was after the Zentradi experincing culture shocks and military data which we already knew about would have been a bit boring. As for how good they were as spies, well you can't really say that as they were experincing a completely alien culture that they had noidea of how it worked, or even how the dress sense was.
Thats Kamjin, Kaifun was that annoying passafist that was trying to get with minmei.
Thats what I was getting at, the main problem with the tatic I suggested is changing the odb to the ppb being how long it would take and in that time what could britai's ship do.
Also a LOT of those ships were used to clean the Earth in the Zentradi assult.