Around 150 German guns had been identified on the corps ' frontage .
The medium regiments of 5 AGRA began firing CB tasks ( ' DROOP I ' and ' DROOP II ' ) at 17.00 , four hours before H - hour .
Around 150 German guns had been identified on the corps ' frontage , and the medium regiments of 5 AGRA began firing CB tasks ( ' DROOP I ' and ' DROOP II ' ) at 17.00 , four hours before H - hour .