Champs
MSABHRC = Mintex MSA British Historic Rally Championship    
MNHRC = Motorscope Northern Historic Rally Championship    
PETCH = SG Petch ANECCC Rally Championship    

Class
B1/B2 = Category 1 - registered before 31/12/1967 - Cars up to 1000cc and Cars 1001cc to 1300cc (National A Historic)    
B3 = Category 1 - registered before 31/12/1967 - Cars 1301cc to 1600cc, excluding Twin Cam engine cars (National A Historic)    
B4 = Category 1 - registered before 31/12/1967 - Cars 1601cc to 2000cc, including Twin Cam engine cars (National A Historic)    
B5 = Category 1 - registered before 31/12/1967 - Cars over 2001cc, including all Porsche 911s (National A Historic)    
C1/C2 = Category 2 - registered between 01/01/1968 and 31/12/1974 - Cars up to 1300cc and Cars 1301cc to 1600cc, including 2 value Twin Cam engine cars (National A Historic)    
C3 = Category 2 - registered between 01/01/1968 and 31/12/1974 - Cars 1601cc to 2000cc (National A Historic)    
C4/C5 = Category 2 - registered between 01/01/1968 and 31/12/1974 - Cars over 2001cc, including all Multi-value Twin Cam engine cars (National A Historic)    
D1/D2 = Category 3 - registered between 01/01/1975 and 31/12/1981 - Cars up to 1300cc and Cars 1301cc to 1600cc, including 2 value twin cam engines (National A Historic)    
D3 = Category 3 - registered between 01/01/1975 and 31/12/1981 - Cars 1601cc to 2000cc (National A Historic)    
D4 = Category 3 - registered between 01/01/1975 and 31/12/1981 - Cars (including Twin Cam Multi-value engine cars) over 2001cc (National A Historic)    
D5 = Category 3 - registered between 01/01/1975 and 31/12/1981 - All other Twin Cam Multi-value engine cars (National A Historic)    
E1 = Category 4a - registered between 01/01/1982 and 31/12/1985 - Cars up to 1600cc (National A Historic)    
E2 = Category 4a - registered between 01/01/1982 and 31/12/1985 - Cars over 1601cc (National A Historic)    
F1 = Category 4b - registered between 01/01/1986 and 31/12/1990 - Cars up to 1600cc (National A Historic)    
F2 = Category 4b - registered between 01/01/1986 and 31/12/1990 - Cars over 1601cc (National A Historic)    
G1 = Category K - FIA Appendix K Cars registered before 31/12/1985 - Cars up to 1600cc (National A Historic)    
G2 = Category K - FIA Appendix K Cars registered before 31/12/1985 - Cars over to 1601cc (National A Historic)    
M1 = Cars conforming to 2017 MSA Technical Regulations. All cars must have a valid MSA Competition Car Logbook (CCLB) - Cars up to 1400cc (two wheel drive only) (National B Modern)    
M2 = Cars conforming to 2017 MSA Technical Regulations. All cars must have a valid MSA Competition Car Logbook (CCLB) - Cars 1401cc to 1600cc (two wheel drive only) (National B Modern)    
M3 = Cars conforming to 2017 MSA Technical Regulations. All cars must have a valid MSA Competition Car Logbook (CCLB) - Cars 1601cc to 2000cc (two wheel drive only) (National B Modern)    
M4 = Cars conforming to 2017 MSA Technical Regulations. All cars must have a valid MSA Competition Car Logbook (CCLB) - Cars over 2001cc (two wheel drive only) (National B Modern)    
P1 = SG Petch ANECCC - Up to 1400cc    
P2 = SG Petch ANECCC - 1401cc to 1600cc    
P3 = SG Petch ANECCC - 1601cc to 2000cc    
P4 = SG Petch ANECCC - 2001cc and over    

Champs
FIACELTIC = FIA Celtic Rally Trophy    
MSABRC = MSA British Rally Championship    
PETCH = SG Petch ANECCC Rally Championship    

Class
RC2 = S2000-Rally: 1.6T engine with a 28mm restrictor, S2000-Rally: 2.0 Atmospheric, Group R5 (VR5), Group NR4 over 2000cc (current N4)    
RGT = RGT Cars    
RC3 = Group A over 1600cc to 2000cc, Super 1600, R2 (atmo over 1600cc and up to 2000cc – VR2C and turbo over 1067cc and up to 1333cc – VR2C), R3 (atmo / over 1600 cc and up to 2000cc – VR3C and turbo over 1067cc and up to 1333cc – VR3C), R3 (turbo / up to 1620cc / nominal – VR3T), R3 (diesel / up to 2000c    
RC4 = Group A up to 1600cc, R2 (atmo over 1390cc and up to 1600cc – VR2B and turbo over 927cc and up to 1067cc – VR2B), Kit-car up to 1600cc, Group N over 1600cc and up to 2000cc    
RC5 = Group N up to 1600cc, R1 (atmo up to 1600cc – VR1A/VR1B and turbo up to 1067cc – VR1A/VR1B)    
JRBRC = Junior BRC + Cadet BRC - R2 (atmospheric over 1390cc up to 1600cc – VR2B and turbo over 927cc up to 1067cc – VR2B)    
BRC1 = S2000-Rally: 1.6T engine with 28mm restrictor, S2000-Rally: 2.0 atmospheric, Group R5 (VR5), Group R4 (VR4)    
PRODBRC = Production BRC - Group NR4 over 2000cc    
BRC3 = Group A over 1600cc up to 2000cc, Super 1600, R2 (atmospheric over 1600cc up to 2000cc – VR2C and turbo over 1067cc up to 1333cc), R3 (atmospheric over 1600cc up to 2000cc – VR3C and turbo over 1067cc up to 1333cc), R3 (turbo up to 1620cc nominal – VR3T), R3 (diesel up to 2000cc nominal –VR3D)    
BRC4 = R2 (atmospheric over 1390cc up to 1600cc – VR2B and turbo over 927cc up to 1067cc), Group A up to 1600cc, Kit-car up to 1600cc, Group N over 1600cc up to 2000cc    
BRC5 = Group N up to 1600cc, R1 (atmospheric up to 1600cc – VR1A/VR1b and turbo up to 1067cc – VR1a/VR1B)    
CLASS 1 = NRC - All 2WD non-homologated cars up to 1450cc    
CLASS 2 = NRC - All 2WD non-homologated cars 1451cc up to 1650cc    
CLASS 3 = NRC - Front wheel drive non-homologated cars 1651cc up to 2050cc    
CLASS 4 = NRC - Rear wheel drive non-homologated cars 1651cc up to 2050cc    
CLASS 5 = NRC - All 2WD non-homologated cars over 2051cc    
CLASS 6 = NRC - Any 4WD car not classified in Class 7    
CLASS 7 = NRC - Any derivative of FIA R5 car outwith its homologation    
CLASS LR = All Land Rovers    
CLUB = Pirelli Clubman Challenge    
P1 = SG Petch ANECCC - Up to 1400cc    
P2 = SG Petch ANECCC - 1401cc to 1600cc    
P3 = SG Petch ANECCC - 1601cc to 2000cc    
P4 = SG Petch ANECCC - 2001cc and over    
P5 = SG Petch ANECCC - All 4WD cars