Thanks for your detailed comments freecia. I'm in Switzerland and the bag is not around to check out.

I'm fine if 46l is an overstatement of volume - whatever the true volume is it is likely to be relatively high and I am more impressed with the weight and my past experiences with Osprey's backpacks.

I don't use packing cubes, shirt folders or the like. A zip loc bag for liquids and a mesh ditty bag for cables is as segmented as I get. Any odd corners I can usually find a use for.

Do you (or anyone else who can handle one of these) think I can get a laptop that is, say 2cm thick in the back panel? Between getting the laptop in there and the toiletries in the top pocket I can see this bag working well at security.

I dislike having a second bag and some airlines I use don't allow for that, so my laptop needs to find a home. If the back panel pocket is not deep enough (I worry about the handle restricting the depth there), then that means storing it in the main compartment or the back pocket of the main flap, and either of those locations means unzipping the main zipper and unsnapping the compression buckles at the top corners. Not ideal but otherwise I like that compression design.