Hi Sue,
Thanks for the 1841 info managed to find it on Ancestry after that, they had transcribed the surname as Cockell so put in a correction in case someone else is looking. Did Thomas and his first wife have a Mary Ann around 1820ish. Robert on the 1851 census was living with a family called Creer in Scotland is this a connected name?
The IGI has an Edward son of Peter Corkill and Elinor born 1817 which would close up that gap a bit