Many thanks for the replies folks!!
Apparently, during a bad drought in the mid-70's, the factory workers were told that they had to find ways of saving on water, etc. On some old plans of the area, a well was discovered and staff began uncovering the site. (Hence the name Wellhead, I presume?) This was said to be something left over from when there was a starch factory on the site in the early 1900's, run by Germans.....?
Regards,
Nick