Hello Katie
Did you know there's a topic posted on the Bedfordshire Lookup Requests for Kisby Cotching - where in my reply I've found a William Rainbow, grandson born 1843 Aspley Guise, in the family of Kisby Draper.
The IGI has WR's christening, with parents John Rainbow & Eleanor. From the 1851 census John Rainbow was born Yardley Hastings in 1805. The IGI in turn has his christening, naming parents Caleb Rainbow & Hannah.
Could these Rainbows be linked - is there a pot of gold at each end

Regards John