Shame they haven't answered this , as it's the only thing holding me back from buying

We appreciate your interest. The Mx Key Mini keyboard will fit. Though we haven't tested the Master 3, it may be veryyy close if not on the fringe of being just a bit too bulky for the cabin. The best way to be sure would be through personal testing or visiting a nearby retailer that may have stock. Our store finder located on our website can be useful for presenting nearby retailers. All the best!

@@bellroy_official the mx master I can do without as I sometimes use Logitechs slimmer travel mouse. But that's great news about the mx mini. Thanks for the info, I'll deffo be picking one up soon then