Aliro Group, led by Charter Hall co-founder David Southon, has lobbed a $403 million takeover offer for ASX-listed Australian Unity Office Fund, with an all-cash bid that has won the backing of the vehicle’s largest shareholder.

Put forward on Friday night after market close, the offer follows a period of some turmoil for the listed fund. In January, it dumped an ambitious plan to merge with an unlisted commercial property fund, also run by Australian Unity, to create a $1.1 billion portfolio after opposition by investors.