Many thanks @NancyJohnson, I felt a right idiot, I usually run the two cabs from my Mesa head but thought I 'd try them out with the Ashdown Drophead 200, seems I stumbled across a rare combination of an amp that only has a single speaker out (or at least while there are three options only one can be used at a time), and two cabs that can't be daisychained! Something tells me that the life expectancy of a standard ABY box would be rather short coming after the amp, I might be wrong, and if so I'm guessing there's probably a commercially available post-amp signal splitter? Many thanks for the offer of the Separator, it would be good to know fropm other on here whether or not that's going to work π