Nice to see GK- at the top of the list on the wall above WCC and WLO
Of course, GBTT was a regular on R/T and RTT - Selcall 45509 if my memory serves me right. Think we took the occasional OBS and SLT on W/T, probably to keep the R/O's hand in.
The RTT signals from the ship always had a recognisable 'chirp' to them so you'd know exactly who was calling before the equipment synchronised.
Larry +