Club Metro was established last year following the amalgamation of the Cosmopolitan Club and Wanganui Returned and Services Association (RSA).
At the time the agreement was signed on Tuesday neither of the organisation's members had been briefed, but Allen said he expected Club Metro's members to be excited about the partnership.
"It's bringing more people into the club and today every club needs as much support as it can get from its membership base," Allen said.
"We certainly had our teething problems that were no secret at all and were to be expected, but now the members of both clubs [Cosmopolitan Club and RSA] are very comfortable in the new premises and with the new management structure.
"The amalgamation process is now well and truly embedded, we've got a very enthusiastic staff, board and committee."
Grey Power has yet to shift into the new location but it's expected the move will happen within the next few weeks.
Grey Power Wanganui president Graham Adams said it was time for the organisation to establish a presence in the CBD.
He said having an office will make it easier for members who don't use internet banking to pay their subscriptions, and with Kiwibank phasing out cheques early next year.
"It's a step that will be welcomed by our members for the convenience it allows."
Adams said it's likely the Grey Power office will be manned three days a week for around three to four hours.
