Meanwhile, Citra - the Charity IT Resource Alliance - has pulled back from submitting an alternative bid to run the hub, saying it would only damage the sector further.
Citra chair John Tate said his group would attend the meeting and try to make progress.
These conciliatory moves follow the publication of a damning report by independent consultant David Carrington, appointed by the ACU in February. He found there were no "serious departures" from the rules by the ICT Consortium, but criticised it and most key bodies, including the ACU.
He concluded: "The problems that arose were avoidable and all involved share some of the responsibility for what has been a sorry and exceptionally time-consuming and energy-sapping saga.
"The charity sector is said to be preoccupied with the importance of maintaining public trust and confidence. For so many of the leading organisations within the sector to have demonstrated such an intensity of mistrust and mutual lack of confidence in each other has been of no benefit to anyone.
"The chief executives of the leading organisations should have anticipated that the development of the ICT part of the ChangeUp programme could create problems and reputational risk. They could have intervened to ensure that any difficulties... between them and their organisations in the past - or even currently - did not have such a deleterious impact."
The ACU said it would "look for lessons about the way we work with the emerging hubs". It said it would now consider the final business plan from the ICT Consortium in the light of published guidance and the Carrington report.
Citra and the ICT Consortium welcomed the report. Citra said: "It discusses some serious issues, and we are pleased they are out in the open. We look forward to entering into a productive dialogue with the ACU and ICT Consortium."
The ICT Consortium said: "We acknowledge and accept the report's finding that some of the difficulties experienced could have been avoided if the consortium had been more proactive at an earlier stage of our engagement with particular groups."
George Cook, chief executive of Charity Logistics, said he was "taking on the chin" the report's criticism of his organisation and looking for a way forward.
"The litmus test of the consortium's genuine openness will be accepting Citra as a full member," he added.
Early last year, the ICT Consortium won Home Office funding to develop a business plan and was asked to include "appropriate" partners.
When losing bidder Citra applied to join, terms could not be agreed and the dispute broke out. The chief executives body Acevo was a member of Citra last year but now says it has left the organisation.
- See news special, page 4, and editorial, page 22.