There was indeed an RSS intercept station at St Erth on the north side of Steppydowns Rd and an Adcock DF station in the field opposite. A second DF station was added in 1942 in which the operator was located in a metal tank just under the surface of the ground. It too was an Adcock station with four 30ft vertical aerials. It took a long time finding its location, but after speaking to two surviving RSS DF operators and a friend making door to door enquiries locally, its location was recently identified at St Erth Praze in the middle of a field opposite The Smugglers Inn. The station is just visible in the 1946 aerial photos but the tank was probably excavated soon after to permit cultivation. More information can be found on the RSS website www.secretlisteners.org.
Picture of surviving generator building on Steppydowns Rd attached.
Stan