A temporary grid system was established over the site and marked out using canes. The location of the grid was set out using an RTK GPS system theoretically accurate to some 0.01m and referenced to OS co-ordinates. Hand Held: Data was collected using a Bartington Grad 601-2. The instrument consists of two paired sensors and readings are logged at 0.25m centres along traverses 1.0m apart across 30m grids. The collection of data at 0.25m centres provides an appropriate methodology balancing cost and time with resolution as per Historic England guidelines. Two sensors mounted 1m horizontally apart and very accurately aligned to nullify the effects of the earth's magnetic field. Readings relate to the difference in localised magnetic anomalies compared with the general magnetic background. The magnetometer survey has not recorded any magnetic responses that could be interpreted as being of definite archaeological interest. Uncertain zones of increased response and parallel linear trends have been plotted in the survey; they could be formal garden features, including an outbuilding, associated with Preston Hall which once extended into the site. Alternatively, they indicate the remnants of an old trackway. A possible drain or former field boundary have also been mapped. A cluster of anomalies including ferrous responses could mark the location of a World War II Spitfire crash site and stray debris; but the removal of trees could also be an alternative explanation. Two underground pipes have been detected along with a zone of disturbance which is probably associated with the construction of the adjacent M20.
Thomas Cockcroft (2025) studied this question.