In this question I asked about the meaning of the assignment "depot battalion" in Hart's Annual Army List, a book that lists the assignments of every British officer in the Victoria era, each year.
It appears to mean the officer was assigned to a sort of reserve battalion associated with a regiment, rather than to a service battalion.
However, listings like the third one on this page do not indicate which regiment the officer was assigned to, only that they were assigned to some depot battalion.
Is there some general way to determine which regiment a person was assigned to?
Failing that, why were such detailed records kept of most assignments, but not those to depot battalions?