Complex sentence: The Beer Quarry Caves were of great use to smugglers as they could be used to store contraband, hidden from the excise officials, one cave that was used was the Adit between Branscombe and Beer Head.
Split into simpler sentences: The Beer Quarry Caves were of great use to smugglers as they could be used to store contraband, hidden from the excise officials. One cave that was used was the Adit between Branscombe and Beer Head.