There is lots of information in the RAFCommands link above, read it again:
From 1665 HCU ORB;
“Two unit pilot instructors, F/O A Austin DFC and F/O F (sic) G Falconer DFC DFM
1665 HCU and 81 OTU were both at Tilstock for a time and were the training units of RAF 38 Group
http://www.rafweb.org/OTU_4.htm
http://www.rafweb.org/Stations/Stations-T.htm#Tilstock