The Department for International Development (DFID) has contracts with third party suppliers for a number of services which are carried out on DFID premises. Information on the name of contractors and the services provided is available on the DFID website at:
http://www.dfid.gov.uk/Working-with-DFID/Procurement/Contracts-let/
It is not possible to provide the number of staff broken down by civil service grades. Union recognition agreements are a matter between our suppliers and their employees.