Home Counties: 

AL = St. Albans, Hertfordshire; CB = Cambridge, Cambridgeshire; CM = Chelmsford, Essex; CO = Colchester, Essex; EN = Enfield, Middlesex, IG = Ilford and Barking, Essex; IP; RM = Romford, Essex; SG = Stevenage, Hertfordshire; SS = Southend-on-Sea, Essex; WD = Watford 

London:

E = East London; EC = City of London; N = North London; NW = North-West London; SE = South-East London; SW = South-West London; W = West End, London; WC = West Central London

South Central England:

GU = Guildford, Surrey; HA = Harrow, Middlesex; HP = Hemel Hempstead, Hertfordshire; RG = Reading, Berkshire; SL = Slough, Buckinghamshire; UB = Southall and Uxbridge, Middlesex

South-East England:

BN = Brighton, East Sussex; BR = Bromley, Kent; CR = Croydon, Surrey; CT = Canterbury, Kent; DA = Dartford, Kent; KT = Kingston-upon-Thames, Surrey; ME = Medway, Kent; RH = Redhill, Surrey; SM = Sutton, Surrey; TN = Tonbridge, Kent; TW = Twickenham, Middlesex