There is still something odd about the numbering.
TR9D should be 10D/10470, see here:
http://home.btconnect.com/gmb/airequip.htm
10D stands for Radio Receivers andTransmitters
10A stands for Miscellaneous Radio Equipment
See here:
http://aircraft-cockpits.com/ww2rafrefno.htm
If the one you found is designated 10A/10470, could it be a modified TR9D rather than a standard one?
Mark