If you raise jurisdictional objections to an adjudication, for example that the contract is not in writing, you must make it clear at the time, preferably in writing, that you reserve your position to raise objections at any subsequent enforcement hearing. You must state that not only do you raise an objection on grounds of lack of jurisdiction but that you are not agreeing to be bound by the decision the adjudicator reaches on the issue and that you reserve your right to raise objections in the future. If you don't, like the defendant in this case, you will be taken as having agreed to be bound by the adjudicator's conclusions on jurisdiction and you will be stuck with his decision.

[Harris Calnan Construction Co Ltd v Ridgewood (Kensington) Ltd (15.11.07)]