Chris,
Ryan posts a lot of truths there.
My Dart ancestors came from Crediton, and one of them was John Dart, a builder. He got a lot of church work through "Buller influence" according to Venn.
If possible, you should go to your library and see if they have a copy of Venn, as he almost certainly would have discussed the influence of the Buller family on Crediton in his two volumes on Crediton, and there is a good chance that your ancestors may be found in Venn if they lived and worked for any time in Crediton - especially if they worked in such an important household.
The passage I refer to above concerning "Buller influence" is an extract from "Crediton", Page 283, Volume 2, by T.W. Venn (October 1957 revision). As far as I am aware, these volumes are only available in substancial libraries.
Adrian