Hi Testiles
You are correct in assuming that I left it at the default 0.5 minutes when I ticked "remove sequences". In the 'blu-ray" tab.
Now, should there be menus on these discs?... Please don't repeat this to anyone but I downloaded rips of "Blue Underground" blu-rays from a private russian site. There are menus on those. I made ISOs out of the files I downloaded using DVD Fab. When those discs play (the three of them), there is a small sequence with the FBI warning, an animated company logo, and then an animated menu.
edit : I received another blu ray from Blue Underground today, "Zombie". It has 2 discs, and I did a copy of them. The ISO of the first disc plays fine (I get the animated menu), only it hasn't been "named" : it is called "BDROM". The ISO of the second disc, which doesn't play (I get the black screen) is called "ZOMBIE_DISC2".