The Further Education Development Agency will dispose of its two sites in Blagdon, near Bristol, and its two central London offices by July 1999.
Confidential board papers obtained by The TES reveal that the four options for relocation will cost anything up to Pounds 2.3 million.
Proposals to retain the Coombe Lodge training centre near Bristol and FEDA's two existing London offices would have saved Pounds 431,000. A plan to move out of Bristol but consolidate the quango in its existing London offices would have cost just Pounds 602,000.
The favoured option - a new London HQ - was costed at between Pounds 1. 934m and Pounds 2.368m.
Only a plan to create a new Midlands headquarters would have been more costly, at Pounds 2.956m.
FEDA officials will now open negotiation with the FEFC to obtain funding for the move.
The plans - as first revealed in The TES earlier this month - will include a "cyber cafe".
The staged reorganisation would involve selling the quango's Mendip training centre near Bristol, and developing the nearby FE staff college, a former stately home, as a conference facility.
FEDA officials say the new headquarters will be a "natural drop-in and information centre for college governors, principals, senior staff and other key clients".
A statement from FEDA chairman Terry Melia said: "These decisions have been taken on the basis of a clear board vision and strategy for the future of FEDA as a leading-edge provider of support and services to the FE sector into the 21st century.
"FEDA needs to be a 'virtual' organisation delivering throughout the country. In order to achieve this, FEDA needs a single operational centre in London to ensure efficient and robust support for a strengthened network of regional centres, and to enable increasingly local delivery."
An inspection report, thought to be critical of FEDA management, is due to be released today, along with new guidance from Education Secretary David Blunkett.