I had a closer look at an aerial view of Spurn's 'neck' - the area where the sea defence blocks are. I compared it with the same section of the 1852 map (From: Dept. of Geography University of Hull) and tweaked the two maps to the same scale. The image shows the maps overlaid. See the enlarged version.
The full yellow line shows what remains of the Spurn peninsula at an "ordinary spring tide" in 1852. The dashed yellow line running vertically through the middle of the image roughly outlines the former shore of Spurn towards the Humber - a strip of sand and shingles. On the enlarged version of the image you can see that the group of sea defence blocks are positioned between these two yellow lines. So, the defence blocks spreading along the seaside today in this area happen to outline the riverside of Spurn in the 1850's.
I'm thinking of the static blocks of stone - meant to protect against the dynamic forces of wind, weather and waves - and the shifting landscape. Taking these aspects into account I'd like to mark a stretch of the defence blocks which by chance outline some of the 1852 Spurn. I will need to have another look at the real Spurn - the tides in this area and the actual blocks.