[Herald1360]

AFAIK the cells in the old battery (the 800) are the same size as the cells in a Lantern Battery (996), so if you're really keen you can manufacture a drop in replacement with some card and a couple of bits of brass strip.

I believe for a while there was a purpose designed adaptor made to drop in two D cells (U2 in old Ever Ready) but I've never actually seen one. It might be possible to modify a two cell D holder to suit.

The cycle lamp I preferred was similar but with a simple screw down contact onto the top strip of the battery. This really had nothing to go wrong, not even switch contacts.

I reckon the old ones were just too reliable to be a regular earner, I'm sure the switch mechanisms on all the later replacements were carefully designed to wear out after a year or two of constant use. There was much ado about better beam patterns etc from the new plastic lenses and prefocus bulbs, but there is no technical reason why the same lens treatment couldn't have been applied to the old style lamps which were easy enough to focus anyway..