When the car was built one of the last things fitted would have been the battery, The brake lines would have been installed earlier in the build.. .
jbk, you have put you finger on the problems of incremental machine design over time. No logic to it.
The result that I dislike most is the accumulated problems of ever more difficult access. Happily trads remained simple enough for owners to resolve many non-
invasively. So when I encounter one, I try to resolve it with with extra labour at home, rather than struggling with it roadside 1000 miles away while my wife goes
shopping.
The battery access and removal is one such area. I have no wish to turn myself into a pretzel merely to change a battery.
Access was easy. It is one of the features of the added tool bins I made in the axle area cover.
https://www.gomog.com/allmorgan/rearstorage1.jpgBattery Removal, merely meant buying a battery tray ]after very careful measurements. (very careful measurements cost nothing) and battery trays can
be had for 10 quid.
I bought a fancier polished billet one shown below.for 50 whatever I hinged (use ss) the forward side at the tiny shelf (the shelves changed
size over time) or used the metal tabs that another other had, (shown above). The hoop suspension cars (post 1992...from memory) provide the front holding point.
Most hoops come with a drilled hole for the needed thread rod
that I use with a butterfly nut. Loosen/undo the nut, and the battery swings on the hinge to the
ground. Takes seconds. If you have a later screwed down axle compartment cover, change it to the earlier removal method.
As we see so often these days, not all
"progress" makes sense. 
Lorne
http://www.gomog.com/TEMP/BatteryTray1.jpg
