Which LDZ / Local Distribution Zone you are in has a significant effect on your gas bill. This applies to both the standing charges and the unit rates or price per therm. Unfortunately, it’s also something you can’t change, short of moving your business. Your LDZ also dictates who you will need to contact to upgrade or downgrade your supply or if you are looking for a new supply.
The EA area covers the following Postcodes

Towns
Abbots Langley |
Aldeburgh |
Arlesey |
Ashford |
Attleborough |
Baldock |
Barnet |
Beccles |
Bedford |
Berkhamsted |
Biggleswade |
Bishop’s Stortford |
Borehamwood |
Braintree |
Brandon |
Broxbourne |
Bungay |
Buntingford |
Bures |
Bury Saint Edmunds |
Bushey |
Cambridge |
Chatteris |
Chelmsford |
Chesham |
Clacton-on-Sea |
Colchester |
Cromer |
Dereham |
Diss |
Downham Market |
Dunmow |
Dunstable |
Ely |
Enfield |
Epping |
Eye |
Fakenham |
Felixstowe |
Frinton-on-Sea |
Great Yarmouth |
Halesworth |
Halstead |
Harleston |
Harlow |
Harpenden |
Harwich |
Hatfield |
Henlow |
Hertford |
Hitchin |
Hoddesdon |
Holt |
Hunstanton |
Huntingdon |
Ipswich |
Kings Langley |
King’s Lynn |
Knebworth |
Leighton Buzzard |
Leiston |
Letchworth |
Little Walsingham |
Livingston |
Lowestoft |
Luton |
Maldon |
Manningtree |
March |
Melton Constable |
Milton Keynes |
Much Hadham |
Newmarket |
North Walsham |
Norwich |
Ongar |
Peterborough |
Potters Bar |
Radlett |
Rickmansworth |
Royston |
Saffron Walden |
Saint Albans |
Saint Ives |
Saint Neots |
Sandy |
Sawbridgeworth |
Saxmundham |
Shefford |
Sheringham |
Southminster |
Southwold |
Stansted |
Stevenage |
Stowmarket |
Sudbury |
Swaffham |
Thetford |
Tring |
Waltham Abbey |
Waltham Cross |
Walton On The Naze |
Ware |
Watford |
Wells-Next-the-Sea |
Welwyn |
Welwyn Garden City |
Wisbech |
Witham |
Woodbridge |
Wymondham |
Counties
Norfolk |
Suffolk |
Essex |
Hertfordshire |
Bedfordshire |
Kent |
The EA Distribution Zone is operated by Cadent