Ok, so I have had my unit for a day or so, and I now have a reasonable grasp on its workings. The one thing I have not yet worked out is - Some professionally purchased profiles have no cab. I could not work out why a few of them sounded awful, until I saw the cab light was unlit. On further investigation, by holding the cab button down, the cab section was telling me it was empty.
Does anyone know why this should be?