Despite the battery conditioner showing a green light (healthy battery) something was amiss .... hazard lights came on, dash lights pulsed on and off, Morgan essentially dead.
Unfortunately my portable jump pack was in another car which is in the bodyshop - and all of this at 7:30am and needing to get to B&C for a service and MOT.
Thanks to Peter J and a few texts back and forth, he told me the battery I needed to buy as the Banner Bull is no longer available..... shot down to Andover, picked up a new battery, installed in the Morgan (which started immediately) and on to the garage where it passed it's MOT.