Champs
A = Motorsport UK British Historic Rally Championship    
B = Motorsport UK Welsh Forest Rally Championship    
C = RACRMC Asphalt/Rally2 Mixed Surface Rally    
D = ANWCC Forest Rally Championship    
E = Crew 25 Rally Championship.    

Class
B1 / B2 = Cars up to 1300cc    
B3 = Cars 1301cc to 1600cc excluding twin cam engine cars    
B4 = B4 Cars 1601cc to 2000cc including twin cam engine cars    
B5 = B5 Cars over 2001cc inc all Porche 911s    
C1 / C2 = Cars up to 1600cc inc twin cam 2 valve engine cars    
C3 = Cars 1601cc to 2000cc    
C4 / C5 = Cars over 2000cc inc all multi valve Twin Cam engine cars    
D1 / D2 = Cars up to 1600cc inc 2 valve Twin Cam engine cars    
D3 = Cars 1601cc to 2000cc    
D4 = Cars over 2000CC inc twin cam multi valve engine cars    
D5 = All other Twin-Cam multi valve engine cars    
E1 = Cars up to 1600cc Registered between 01.01.82 and 31.12.85    
E2 = Cars over 1600cc Registered between 01.01.82 and 31.12.85    
F1 = Cars up to 1600cc Registered between 01.01.86 and 31.12.90    
F2 = Cars over 1600cc Registered between 01.01.86 and 31.12.90    
G1 = FIA Appendix K registered before 31.12.85 Cars under 1600cc    
G2 = FIA Appendix K registered before 31.12.85 Cars over 1601cc    
FIA = Category FIA    
CLASS 1 = Up to 1000cc    
CLASS 2 = 1000cc to 1400cc    
CLASS 3 = 1400cc to 1600cc    
CLASS 4 = All Vehicles that do not comply with classes 1, 2 or 3. Limited to max 1600cc    

Champs
A = Motorsport UK British Historic Rally Championship    
B = Motorsport UK Welsh Forest Rally Championship    
C = RACRMC Asphalt/Rally2 Mixed Surface Rally    
D = ANWCC Forest Rally Championship    
E = Crew 25 Rally Championship.    

Class
B1 / B2 = Cars up to 1300cc    
B3 = Cars 1301cc to 1600cc excluding twin cam engine cars    
B4 = B4 Cars 1601cc to 2000cc including twin cam engine cars    
B5 = B5 Cars over 2001cc inc all Porche 911s    
C1 / C2 = Cars up to 1600cc inc twin cam 2 valve engine cars    
C3 = Cars 1601cc to 2000cc    
C4 / C5 = Cars over 2000cc inc all multi valve Twin Cam engine cars    
D1 / D2 = Cars up to 1600cc inc 2 valve Twin Cam engine cars    
D3 = Cars 1601cc to 2000cc    
D4 = Cars over 2000CC inc twin cam multi valve engine cars    
D5 = All other Twin-Cam multi valve engine cars    
E1 = Cars up to 1600cc Registered between 01.01.82 and 31.12.85    
E2 = Cars over 1600cc Registered between 01.01.82 and 31.12.85    
F1 = Cars up to 1600cc Registered between 01.01.86 and 31.12.90    
F2 = Cars over 1600cc Registered between 01.01.86 and 31.12.90    
G1 = FIA Appendix K registered before 31.12.85 Cars up to 1600cc    
G2 = FIA Appendix K registered before 31.12.85 Cars over 1601cc    
ONE-FOUR = Up to 1400cc    
OPEN = 1401cc up to 2000cc    
OPEN PLUS = 2001 cc and over    
T14 = Up to 1400cc Complying with Tyro specification    
T16 = Up to 1600cc Complying with Tyro specification    
CLASS 1 = Up to 1000cc    
CLASS 2 = 1000cc to 1400cc    
CLASS 3 = 1400cc to 1600cc    
CLASS 4 = All Vehicles that do not comply with classes 1, 2 or 3. Limited to max 1600cc    
W2 = 2wd 8v up to 1400cc    
W3 = 2wd 16v up to 1400cc    
W4 = 2wd 1401cc to 1600cc    
W4A = R2 FIA R2 (B)    
W5 = 2wd 8v 1601cc to 2000cc    
W6 = 2wd 16v 1601cc to 2000cc    
W12 = 2wd Over 2000cc    

Champs
A = Motorsport UK British Historic Rally Championship    
B = Motorsport UK Welsh Forest Rally Championship    
C = RACRMC Asphalt/Rally2 Mixed Surface Rally    
D = ANWCC Forest Rally Championship    
E = Crew 25 Rally Championship.    

Class
W10 = Current and former FIA Group N cars over 1400cc up to 2000cc    
W11 = Current and former FIA Group N and NR4 cars over 2000cc    
W13 = 4wd cars over 2000cc including FIA R4.    
W14 = Current and former WRC with a sequential gearbox, plus current and former S2000 and R5 cars