The real legal question, according to case law is whether or not the people party to the "contract" acted in such a way as to validate that "contract" after the utterance. This would be "understood performance" and would be granted a hearing.
I'm not aware of any conditions that could be performed in the enactment of the "contract" therefore legally I would have to say there is nothing binding either/any of them. The fact that it had been discussed on camera may be taken into account as persuasive evidence, but could also equally be taken as emotive chat, especially considering there were no conditions to perform within either housemate's remit.
I do have a law degree - if all or any of them wish to walk away from the subjunctive chat (if....) I would be happy to represent them. For a price.
