The ICAO code, that is the Short Type that appears in the aircraft list is C130
On the other hand, if you are after the Mode S 6-figure Hex code, all the RAF aircraft will start with 43C
So, if you open MyLog and put ModeS = 43C* in the quick filter then select Today or whatever period you want, and click Filter - then you will see all the Brit Mil aircraft detected.