I had this same problem a few weeks ago. I was after a bag that I could use in the UK as well as taking abroad. After much thinking I decided to scrap this idea and for the UK go with a sturdy plastic crate on wheels from B&Q.
For taking abroad I got the same bag as NickB, but in the 80L version. It's a cool looking bag, built well, and doesn't have a dive brand advertised on the side. There is the argument that being a 'known' brand advertises that expensive stuff is inside, but if there are Mares, TUSA, (insert a dive brand here) bags going around as well, they are going to be first hit. Plus a number of other people on YD have these bags and haven't had any trouble.
Oh and considering I got it brand new for £69 probably helped in the decision making process
