Complex sentence: Moorehead 1997, pp.146--147 That evening Birdwood had been ashore to check on the situation and satisfied returned to HMS "Queen", then around 21:15 he was asked to return to the beachhead.
Split into simpler sentences: Moorehead 1997, pp.146--147 That evening Birdwood had been ashore to check on the situation, and, satisfied, returned to HMS "Queen". Around 21:15 he was asked to return to the beachhead.