I'm new to roots chat, so ignore the mistakes.
I am researching pubs in South Holland district, and notice chipladdies post re. the Whaplodes. I know its from 2011, but did you sort it OK?
The basic bit is to understand there are two sorts of parish: civil parishes are about day-to-day governance and there is usually a parish council to administer local issues, e.g. street lighting in the parish where I live.
Ecclesiastical Parishes are the other sort. They are to do with the Anglican Church and are about how bishops manage the parishes within their diocese.
In the Whaplode example, Whaplode is a civil parish, extending from the Wash, more or less, to the Cambridgeshire border, and the parish council will represent the whole, possibly split into Wards for election purposes]. Within this parish are two ecclesiastical parishes, Whaplode St Catherine and Whaplode Drove. I'm not sure how these are grouped today: I think one of the Whaplodes is grouped with [shares its priest with] one of the Holbeaches, which is divi'd up in a similar way.
If I can master the attachment facility of this site, I'll send a copy of an outline-only map [a 'skeleton' map] of South Holland parishes which clearly shows the long/narrow format of fenland parishes. It originates from the planning department,[so maybe you could get one direct?] and has no copyright issues attached to it.
As for my own research, if anyone has any info, or the golden touch of a photograph, about the Chequers Inn in Tongue End, please let me know.