Huntingdonshire Archives are a fabulous resource for studies of Holywell-cum-Needingworth, and I am really most grateful to the staff there for all the help they have given me in my researches.
(I expect that you will be seeing a lot more of me, as I pursue leads and look for evidence!)
The catalogue for both Cambridgeshire and Huntingdonshire Archives can be found here. I have searched this for documents relating to our village and am gradually working through them when I visit.
Huntingdonshire Archives are located within the premises of Huntingdon Library, and the library has also been a great help to my researches. They not only hold many relevant books, but also most of the relevant maps. The Library catalogue can be found here.