Complex sentence: The group was split up and sold but the new owners did not survive long as in 1877 the Old Park site, which in 1810 had been the second biggest ironworks in Britain, closed down.
Split into simpler sentences: The group was split up and sold but the new owners did not survive long. In 1877 the Old Park site, which in 1810 had been the second biggest ironworks in Britain, closed down.