Complex sentence: The 1/4th London and the London Scottish advanced behind a creeping barrage fired by batteries in Angle Wood Valley in enfilade towards Bouleaux Wood, which was particularly accurate.
Split into simpler sentences: The 1/4th London and the London Scottish advanced behind artillery fire from the flank towards Bouleaux Wood. A creeping barrage fired by batteries in Angle Wood Valley in enfilade and was particularly accurate.