Using Familysearch, apart from the baptism of John Cottrell 1811, the other family events which I can find associated with John and Elizabeth Cottrell in and around Burlescombe are as follows:

Elizabeth Cottrell
Christening 1 January 1809
Uffculme, Devon, England, United Kingdom
Parents: John Cottrell, Elizabeth

Dennis Cottrell
Christening 9 October 1814
Burlescombe, Devon, England, United Kingdom
Parents: John Cottrell, Elizabeth

William Cotterell
Christening 17 January 1819
Burlescombe, Devon, England, United Kingdom
Parents: Elizabeth Cotterell (widow)

I suspect their marriage is recorded in the Exeter BTs as: John Cotterell of Burlescombe and Elizabeth Lucas of Collumpton (sic) on 23 April 1806 at Burlescombe. There seems to be some confusion as to the date (1805 or 1806) but after examining the image (see
https://www.familysearch.org/ark:/61903/3:1:3QSQ-G94Y-98F8?i=233&cc=2515875&personaUrl=%2Fark%3A%2F61903%2F1%3A1%3AQPWR-8YGP ) I think it's 1806.

The births seem to be well spaced. I wonder if John the elder was a travelling craftsman who was often resident in other parishes?