Coming a bit late to this ~
Marriage place is recorded as Burford - 3rd Portion (St Mary) on the transcription
A larger snip
I think you have given us a clue as to what might be occurring, Gadget.
F m p also transcribes and mentions 3rd Portion.
The Burford Shropshire Register at the end of 1703, (pencil page numbering 186) says:-
J. Bayly 1d )
Charles Mauffield 2d ) Portions
Amb: Sparry 3d )
It seems the Parish was split into Portions and the events in the Register acknowledge who provided that information.
P C M means - Portion Charles Mauffield (the source).
See also end of 1700.
Mark
Added later: line should read
Charles Mansfield 2d ) Portioners