There were a few agreements as I recall, not just one exclusivity agreement.
None were ever made public so it's not possible to say.
One of the documents submitted as part of the Kirkby stadium bid said: "the willingness or abilities of the Club's Directors to sell all or some of their interests to attract an investor who or which might have the ability in financial terms to fund a new stadium in its entirety or at the very least the shortfall. This is not an option, as the current Directors have no intention of selling any of their interests in the Club".
http://inquiry.knowsley.gov.uk/Core%20Documents/CD%201.1.3%20PlanningStatementRevised.pdf
Page 36, Para 6.1.0