Useful websites you might like to look at include:
The Parish of Fletton https://www.flettonparish.co.uk/
St. Margarets Church, Fletton https://stmargaretschurch-fletton.co.uk/
Peterborough and District Family History Society https://www.peterborofhs.org.uk/
Peterborough Local History Society https://peterboroughlocalhistorysociety.co.uk/
Huntingdonshire Local History Society http://www.huntslhs.org.uk/
Cambridgeshire and Huntingdonshire Family History Society https://www.cfhs.org.uk/
Family History Federation https://www.familyhistoryfederation.com/
The Institute of Heraldic and Genealogical Studies https://www.ihgs.ac.uk/