Hi firstly its not pre treaty C, wrong initial mark and letter R, The initial mark puts it as PTS E or G
PTSE is known from several dies without letter A in EDWARD, L.A.Lawrence (Numismatic Chronicle 1929 p106 - 163, 1932 p 96- 174) lists 7 different dies but none correspond to the die used for your coin, More interestingly is the complete horllx of the legend from ANGL Z onwards it appears to read FRALIIB???? This legend is not given in LAL.
It would be usefull to see the reverse of the coin to determine if PTS E or PTSG