Pyrrho Investment, a Hong Kong-based property investor, has called in the agency after it claimed it had been frozen out of the bidding process in favour of hedge fund BlueGem Capital Partners.
Hogarth MD Reg Hoare and director Katie Hunt will lead the account.
On 7 May, Liberty announced it had agreed a £42m, 186p per share bid from BlueGem. But Pyrrho said last Friday it had been denied the chance to make a higher offer after its initial 185p per share bid was rebuffed.
Liberty, which is using retained financial adviser Baron Phillips Associates, on Monday dismissed this accusation, stating it never received an increased offer from Pyrrho.