(Sharecast News) - Tritax Big Box said it had agreed with lenders to extend the termination date of a new £350m unsecured revolving credit facility to December 10, 2023.The margin payable under the facility of 1.10% a year over three month LIBOR remains unchanged and the facility retains its uncommitted £200m accordion option, Tritax said.It has one further extension option available under the facility.The agreement further extends the company's weighted average debt maturity (excluding the existing £250n short-term debt facility) to 8.7 years.