Marshall? Edge?? Are there any pics of this? Would be very curious...
The only place I've seen it is when Edge was doing that BBC doc that he was showing of his rig....there was a half stack behind him. And its also in the Beautiful Day Video even tho i believe beautiful day was done on a Vox thats what Edge said in the interview.
You're right about the BBC doc, but in the "Beautiful Day" video he's using HiWatts, not Marshalls.
And yes, I also wouldn't trust what he's using in videos, rarely is that actually used for the recording!
There are pictures all over the net showing it, Usually on the left of his effects rack in some live settings not to mention studio pictures & of course the BBC documentary where he actually states that its a new addition. Its even in his sound check from it might get loud, You just get a glimpse of the back of it next to his rack when the camera pans back while he's playing Bad.
Its also listed in some of his gear lists as a 1987 which is a JMP50 with a Mick Ralphs owned 4x12.
Live shots & videos of Edge back in the late 70's early 80's also sometimes show him using a Marshall JMP50 2x12 combo so he's no stranger to Marshall Amps!