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
  Dousland Map BH18
SX536688
SRS diagram D1 (old and new boxes)
S 932 Tigley Map BM16
SX762605
SRS diagram X19
Prices are shown here.