I am related to John and Eunice (Denman) Pook. They were apparently active in the independent church of S. Petherton. If you go to this website, someone has transcribed a bunch of records: http://www.southpethertoninformation.org.uk/roundwell_.htm
There are a lot of Denmans and Horseys there. I did not find an Oliver, but I can't help but think these are related to you somehow.
There was another couple Robert and Annis (Denman) Pook, who I'm thinking might have been related to John and Eunice. Still searching.