RISC OSMap of G.W. SignalboxesRISC OS
http://www.svrsig.org/gwmap/GWMap.htm
Sxxxx numberSignal Box nameView on map squareOther information including SRS diagram number
  Litchfield Map DF39
SU460538
SRS diagram D84 (old and new boxes)
  Lodge Bridge Map DG36
SU450428
SRS diagram S813
  Whitchurch Map DF37
SU460480
SRS diagram D85 (old and new boxes)
Prices are shown here.