* Proceeds will be used to pay down debts
* Deal due to complete March 31
(adds details)
LONDON, March 30 (Reuters) - UK property investor Warner Estate Holdings has sold one of its biggest shopping mall investments in deal worth 91 million pounds ($129 million), as it battles to shore up its balance sheet through asset sales.
Last month, the company said it was in talks with its lenders to resolve a slew of debt covenant-related issues triggered by a record UK commercial property slump in 2008.
In a statement on Monday, the company said its Agora Max Limited unit -- a 50:50 joint venture with Halifax Bank of Scotland -- has agreed to sell the Pallasades Shopping Centre in Birmingham, England to Birmingham City Council.
Proceeds from the cash sale, which is due to complete on March 31, will be used to reduce the debt within the partnership structure, Warner said.
Warner's shares gained 5.6 percent and were trading at 19 pence by 0856 GMT, outperforming a 2 percent fall in the FTSE 350 Real Estate Index.
Warner appointed Rothschild in November to assist in discussions with its banks and to advise the board on the most appropriate capital structure for the company.
(Reporting by Sinead Cruise)
(See www.reutersrealestate.com for the global service for real estate professionals from Reuters)