whilst research some recent acquisitions, i found this list of medal prefixes on another forum, thought id post it on here as it may help others.
sorry if this has already been covered.
A - KRRC (Early wartime recruits).
A - RSF, Cameronians & AOC.
B - 26/RF (City of London Bankers).
B - KRRC, Rifle Brigade & Cameronians.
C - KRRC (16th Battalion onwards).
C - 1/R Munster Fus. (Garrison Bn.), Middx. Regt. & Rifle Brigade.
CHT - Corps of Horse Transport - ASC.
CMT - Corps of Motor Transport - ASC.
D - Dragoons & Dragoon Guards.
DG - Dragoon Guards.
DM - Driver MT - ASC.
E - 17/RF (Empire Battalion).
F - 17 & 23/Middx. Regt. (Football Battalions).
G - 1, 2 & 3/RIF (Garrison Battalions).
G - Prefix found on various Home Counties regiments (Service Battalions).
GS - See above.
GS - Cavalry regiments (War service only).
GS - General Service.
H - Hussars.
J - 38, 39 & 40/RF (Jewish Battalions).
K - Royal Lancaster Regt. (The King's Own) & Cambridgeshire Regt.
L - Lancers.
L - Prefix found on various Home Counties regiments (Regulars).
L - 3/SWB.
M1 - MT Section - ASC.
M2 - Electricians - ASC.
MS - Mechanical Specials (trade) - ASC.
MT - Mechanical Transport (trade) - ASC.
N - RAMC.
O - Rifle Brigade.
P - Military Police.
P - Dragoon Guards.
PS - 18, 19, 20 & 21/RF and 16/Middx. Regt. (Public School Battalions).
PW - 18, 19 & 26/Middx. Regt. (Public Works Battalions - later Labour Corps).
R - Remount Section - ASC.
R - KRRC (later recruits up to 16th Bn.), also Manchester Regiment.
RX - Remount Section - ASC.
S - Supply - ASC.
S - Highland Regiments (wartime enlistments).
S - Home counties regiments (3rd [Militia] Battalions).
S - Rifle Brigade, Dorset Regt., R Munster Fus., AOC, RA & RAMC.
SB - 10/RF (City of London Stockbrokers Battalion).
SD - 11, 12 & 13/R Sussex Regt. (South Downs Battalions).
SE - Army Veterinary Corps (Special Enlistment for duration).
SPTS - 23 & 24/RF (Sportsmans' Battalions).
SS - Supply Special (trade) - ASC
STK - 10/RF (City of London Stockbrokers Battalion).
T1, T2, T3 & T4 - Horse Transport - ASC.
T - Army Ordnance Corps.
T - Territorial Force.
TF - Territorial Force.
TR - Training Reserve - ASC.
TS - Transport Specials (trade) - ASC.
TSR - Transport Special Reserve - ASC.
W - 13/Cheshire Regt. (Wirral).
W - 38th (Welsh) Divn. Royal Artillery.
WR - Royal Engineers (Waterways & Railways).
Y - KRRC (early wartime enlistments).
Z - Rifle Brigade.