The first pillbox I cam across was a bullet proof Type 24 along the A1123 which was presumably part of the outlying Cambridge defences / GHQ Line as it ran north of Cambridge along the River Cam.
Next up was a Type 28a pillbox for the 2 pounder anti-tank gun on the northern extension of the Eastern Command Line. It is located at Brandon Creek, just to the south of Southery. Note the screw pickets on the roof and the remains of a black finish on the roof to hide the shine form the concrete. I have no idea what the metal rods protruding from the inside of the embrasure where for.
Just a little further north up the road was this Shell proof Type 24.
Part 2 of this thread will look at some of the pillboxes on the northern extension of the Command Line in the Nordelph area.