Complex sentence: The Harringtons lived for a time at 20 Prospect Road in'Stone Hall' then by the 1960's had built St Helen's House on Prospect Road where St Helen's Park remains today.
Split into simpler sentences: The Harringtons lived for a time at 20 Prospect Road in'Stone Hall'. By the 1960s the Harringtons had built St Helen's House on Prospect Road where St Helen's Park remains today.