The ratio in this case was that revocation can be communicated by a reliable source. The estate agent told Dickinson, “Dodds has sold the house to Allan.” Though, what if (in this case) revocation was not communicated; Dodds sold his house to someone else, so how can Dickinson enforce the contract, Dodds does not have possession of the land anymore.
No, so the Court would (probably ) make Dodds buy an equivalent house in a similar condition in a similar location ( no matter what the cost ) and sell it to Dickinson at the original price. But that would only happen if Dodds had paid for the option period from Monday to Friday ( I think there was an option period involved )