▁this ▁period , ▁Har per ' s ▁band ▁were ▁renamed ▁' Ch ips ' ▁and ▁included ▁Andy ▁Roberts , ▁Dave ▁Law son , ▁Henry ▁McC ull ough , ▁John ▁H alse y ▁and ▁Dave ▁C och ran . ▁In ▁April ▁ 1 9 7 8 , ▁Har per ▁began ▁writing ▁lyr ics ▁for ▁the ▁next ▁Led ▁Ze ppel in ▁album ▁with ▁Jimmy ▁Page , ▁but ▁the ▁project ▁was ▁sh el ved ▁when ▁lead ▁singer ▁Robert ▁Plant ▁returned ▁from ▁a ▁break ▁after ▁the ▁death ▁of ▁his ▁son , ▁Kar ac ▁P end rag on . ▁S ays ▁who ? ▁ ▁Following ▁the ▁success ▁of ▁Bull in aming v ase , ▁Har per ▁was ▁asked ▁" to ▁write ▁another ▁record ▁quickly ". ▁Demo ▁record ings ▁with ▁Har per ' s ▁newly ▁formed ▁backing ▁band ▁' Black ▁She ep ' ▁( And y ▁Roberts , ▁Dave ▁Law son , ▁Henry ▁McC ull ough , ▁John ▁H alse y ▁and ▁Dave ▁C och ran , ▁a . k . a . ▁Dave ▁C . ▁Dr ill ) ▁were ▁made , ▁but ▁Har per ▁felt ▁them ▁to ▁be ▁r ushed . ▁The ▁record ▁company ▁who ▁"... w ere ▁in ▁the ▁first ▁stages ▁of ▁a ▁collapse ▁in ▁sales ..." ▁were ▁not ▁interested ▁in ▁the ▁record ings , ▁nor ▁were ▁they ▁prepared ▁to ▁provide ▁studio ▁time ▁when ▁requested , ▁telling ▁Har per ▁to ▁come ▁back ▁in ▁six ▁months . ▁As ▁a ▁result , ▁Har per ▁with h eld ▁the ▁publishing ▁rights ▁to ▁that ▁which ▁had ▁been ▁recorded ; ▁an ▁album