The trust is in the middle of raising £1million to use as an interest-free to the club, which will be matched by Altonwood, and will take ownership of the club in January.
Hounslow Council have also agreed in principle to provide Bees United with a £500,000 interest-bearing loan.
They had two years to reorganise the club's debts and release Altonwood and Noades from bank guarantees, and now have until the end of the year to finalise legal and financial agreements.
Bees United chairman Brian Burgess said: "I must express my thanks to Ron Noades and his colleagues at Altonwood for the flexible approach they are taking in helping us to exercise the option and to make progress towards completing the acquisition of the club.
"The extra time gives us until January to complete our fundraising and sort out the legal details."