Different strokes, different folks, but here are the codes for QF according to Expert Flyer.
Class Codes - QANTAS AIRWAYS
Class Code Airline Description
A QF FIRST
AN QF FIRST CLASS
B QF ECONOMY
BN QF ECONOMY
C QF BUSINESS
CN QF BUSINESS
D QF BUSINESS
DN QF DELUXE NIGHT
E QF SHUTTLE SERVICE
F QF FIRST
FN QF DELUXE NIGHT
H QF ECONOMY
HN QF ECONOMY
I QF DISCOUNT BUSINESS
J QF BUSINESS
K QF ECONOMY
KN QF ECONOMY
L QF ECONOMY
M QF ECONOMY
N QF ECONOMY
O QF ECONOMY
P QF FIRST
Q QF ECONOMY
R QF ECONOMY
S QF STANDARD
T QF ECONOMY
U QF Business - Award
V QF ECONOMY
W QF ECONOMY
X QF Economy - Award
Y QF ECONOMY
YN QF ECONOMY
Z QF First - Award