Rhys W, this week I modified my Vox DA-5 and because you inspired me to get one back in 2009, I naturally thought of you. I moved the unused battery container so that I had space to put velcro inside the cabinet and on the base of the mains adapter. A hole drilled in the back flap and hey presto, I now have a much more easily mobile micro amp.
Very good! My transformer sits halfway along a wall in the living room, so I'd have to re-arrange things if I tried that.
After seeing this I was motivated to try a related idea. The amp sounds great but it can be a little boxy, I know the sound from the line out is decent, so I dug into my box of cables and adapters and plugged the line out into a spare channel on my hi-fi... the sound of this little amp through floor-standing speakers is massive!