Willow - thanks for coming back to the thread. I've no idea about the Cotterills further foward - I'd best explain:
My gut feeling is that Thomas Cotterill is related to Charles Nixon (who was the one I was following) as Charles' mother's maiden name was Cotterill (or variant). When I saw the surname of the family Charles was with I wondered what connection, if any, there was. I've researched all the Nixon siblings (one being my direct ancestor) as far as I can with some really eccentric transcriptions in there. I've "done" the Nixon parents, but not as yet looked for/at their siblings, so if Thomas was an uncle to Charles it would start that generation off.