@Vilas. Thanks for the info.
The fcom I'm looking at still has the following warning for a much later msn number (3xxx)
Note:
DC ESS BUS is lost at landing gear extension.
Consequently, all means of communications are lost since all ACPs are lost.
To verify the list of STATUS INFO, Refer to .......
So I wonder if this has been left in there from previous, very early, msn numbers.