A couple of points. Firstly I can't find "Chivory" or "Gore" although I have found a hamlet called Chivery SW of Luton near Wendover which lies on a direct track from DTY to the Chalfont St Giles VRP.
Below is an excerpt from the OS 1:50000 in the area of the SW corner of the relevant bit of airspace.
The blue line is the direct track from DTY to the VRP, both of which were plotted using the co-ordinates from the AIP.
The red line marked the boundary of the airspace, again plotted using the figures from the AIP.
Assuming you flew the direct track with absolute accuracy then you would appear to have been just inside the airspace. However, the airspace immediately to the SE of this box is LTMA from 2500+ so assuming you went under this (you did didn't you!
) you would already been below the disputed airspace for the second or two that you within its lateral limits.
