Central London includes:

“The City of London”, “The Square Mile”, Belgravia, Bloomsbury, Buckingham Palace, China Town, Fitzrovia, Great Portland St, Grosvenor Square, Harley St, Soho, St. James, Tottenham Court Rd, Marylebone, Mayfair, Piccadilly, Oxford St, Pimlico, Regent’s Park, Regent St, Westminster, Whitehall

Central London
(EC1, EC2, EC3, EC4, W1, WC1, WC2, SW1)

East London
(E1-E18) plus IG (Ilford) & RM (Romford)

North London
(N1-N22) plus EN (Enfield)

North West London
(NW1-NW11) plus HA (Harrow & Wembley)

South East London
(SE1-SE28)

South West London
(SW2-SW20) plus TW (Twickenham)

West London
(W2-W11) plus UB (Uxbridge)

Home counties (around London) & Central Southern England:

Berkshire, Hampshire, Hertfordshire, Isle of Wight, Middlesex, Surrey, West Sussex

Beaconsfield 

Bognor Regis 

Burley 

Burnham 

Caterham 

Chichester 

Cobham 

Cranleigh 

Croydon 

Dartford 

Epsom 

Exmouth 

Guildford 

Hemel Hempstead 

Horsham 

Isle Of Wight 

Kings Langley 

Kingston Upon Thames 

Marlow 

Oxted 

Petersfield 

Portsmouth 

Reading 

Redhill 

Reigate 

Royston 

Slough 

Southampton 

St Albans 

Watford 

Winchester 

Windsor