Thing is, most of us DON'T get up to that sort of stuff in our youth at all. And in this say and age, those sorts of conviction even if 30 years ago absolutely can be a block to FAC. The OP absolutely should apply and be honest about it all, but it could be a bigger issue than some are making out. Anything to do with violence or aggressive behaviour is a red flag for FLOs, and rightly so. The main thing is to be 100% honest. Don't try to spin it or BS. Make clear you're not that person any more and reinforce all of the time that's passed without doing anything wrong etc.