Hi there Swingboats & dawnsh, many thanks for your replies.
My granddad was William Cothard, brother of Richard - his mother was Elizabeth Castle, Chorley's daughter. You are right that Elizabeth 'married' Dicky Codard - his real name was Richard Cowthard, his son Richard (Dickie) has Richard Cowthard on his birth certificate, his other son William (Billie) had William Smith on his birth certificate. From family talk it would appear that Richard Cowthard had run away with the fair and did not want to be found hence why he changed the name. Both Richard and William, however, were known as Cothard throughout their lives and both died under the name of Cothard. My granddad Bill died in 2002 aged 100 and is buried at St Botolph's cemetery near Steyning, he lived in Bramber, West Sussex most of his life and often went to fairs and fetes with his swingboats and roundabouts.