ECO chief executive Andrew Morris is seeking a buyer willing to lease back the venues following the sale. Morris will then continue to run the business on an operational level.
"Our strength is not in being a property owner or investor. It is in the services and experiences we provide within that property," he said.
"The ideal situation is for ECO to work with an investor who wishes to own the buildings and rent them back to us for at least 35 years. Any agreement will be structured to ensure that the ECO team retains complete control."
ECO is now in talks with interested parties.
Private equity firm Candover has a majority 60% stake in ECO, insurer Legal & General has 10% and the Morris family trust owns 25%. Proceeds from the sale would be used to reduce borrowings and allow the management team to boost its 5% stake in the business. Candover will retain a "substantial percentage".
Meanwhile, ECO is hoping to add leisure facilities to the complex as part of a 'work, rest and play' concept. A casino is one idea the venue is looking into.