public:

Chelmsford Borough Council
Colchester Borough Council
Epping Forest District Council
Essex County Council
London Boroughs of:
    Barking & Dagenham
    Barnet
    Camden
    Croydon
    Greenwich
Norwich City Council
Westminster City Council

private:

British Energy Ltd
Barclays Bank
British Airport Authority
British Telecom
Freshwater Group
Imperial Properties Ltd
Legal and General
Lovell Partnerships
Norfolk Enviromental Waste
  Services Ltd
Remploy Ltd
Royal Mail Group Plc

nhs trusts:

Barking & Dagenham
Basildon & Thurrock
BHB Community Healthcare Brentwood, Billericay &   Wickford
City & Hackney
Essex Rivers Healthcare
Ipswich Hospital
NHS Executive London   Region
Norwich PCT
Westminster PCT

housing providers:

Aldwyck
Boston Mayflower
Broadland Housing
Circle Anglia
Cotman Housing
Estuary Housing
Flagship Housing
Islington & Hackney Network
Orwell Housing
The Guinness Trust
Waltham Forest CBHA