Sorry folks, but another close look at various pictures on the net, has revealed that Exide batteries in the Hxxxx series are subtitled DRYDEX, and the DMxxx series are subtitled DRYMAX whatever the colour scheme. That means my DM526 artwork is incorrect as far as the side label and base are concerned I'll redo it, and post it with the grey/version, when I've corrected that as well.
This system would seem to correspond to the Ever Ready Alldry and Battrymax for LT and HT.