These are similar to recent other spectrum auctions and all applications must be received by Ofcom by December 11th 2012 and at the same time Ofcom must have received a £100,000.00 deposit (which is refundable if the bidder doesn't win or withdraws from the auction within the withdrawal timeframe).
Ofcom will have some time to ensure the validity of the application and applicant (they must pass tests to ensure they are valid applicants).
On the 2nd dat Ofcom will tell all bidders of other bidders in their group.
Ofcom then allow 4 days for bidders to notify Ofcom on any group overlaps.
Ofcom then has 3 days to notify successfully qualified bidders, publish them on the Ofcom website and notify them of the last day for withdrawal.
The last day for withdrawal is 2 days following publication.
Ofcom will then publish the list of actual bidders.
Ofcom will use an electronic bidding system which allows bids to be submitted in rounds (this all gets very complicated, especially when an additional opt-in round is added to the process). Ofcom will train bidders on the use of the electronic voting system.
It's expected that at least O2 and Vodafone will bid for the 800MHz spectrum, though 3UK may join in too as they don't have any sub 1GHz spectrum at present. The 2.6GHz spectrum (especially low power licenses) may be more of a jamboree with some unexpected players joining in.