Point 66 in ADVERBS/position is defined as:
‘HARDLY’ in front position followed by an inverted subject and verb, to give focus.
Even though point 66 does not mention past perfect, all the examples given are past perfect.
Point 88 in PAST/perfect simple is defined as:
invert the subject and affirmative auxiliary verb with ‘hardly … when’ to talk about something that happened immediately before something else, in formal contexts.
There are not many examples in iWeb for . Hardly _V _P _V
1 . HARDLY HAD HE DONE 6
2 . HARDLY HAD HE SPOKEN 4
3 . HARDLY HAD HE BEGUN 3
4 . HARDLY HAD HE PASSED 3
5 . HARDLY HAD HE LEFT 3
. Hardly _V * _V when
1 . HARDLY IS SHE ENTRANCED WHEN 1
2 . HARDLY HAVE THEY GONE WHEN 1
3 . HARDLY HAD THEY RISEN WHEN 1
4 . HARDLY HAD THEY FINISHED WHEN 1
5 . HARDLY HAD THEY ANCHORED WHEN 1
6 . HARDLY HAD HE SPOKEN WHEN 1
7 . HARDLY HAD HE LEFT WHEN 1
PELIC STUDENT: Azerbaijani,Female,5,g