Complex sentence: There is a metal hatch in Hawksworth Woods which is actually the entrance to an old explosives store from when the woods were once quarried for stone, this has been mistaken for a World War II shelter.
Split into simpler sentences: There is a metal hatch in Hawksworth Woods which is actually the entrance to an old explosives store from when the woods were once quarried for stone. It has been mistaken for a World War II shelter.