The law on cooling off periods for Estate Agency contracts has changed from a 7 day cancellation period to a 14 day period. Every agency agreement must have a section giving the seller the option to complete and return it cancelling the contract if they change their minds. This is for contracts signed at the sellers home. If the contract is signed in the agents office then this is not the case. However there is also a school of thought amongst trading standards that as the "selling of the contract and presentation to the client " takes place at the property that all agency agreements, irrespective of where they are signed, are subject to this same cancellation period.
It is also contrary to the law of contract for an agency agreement to have a specified period AND require a further period of notice. It can however, have one or the other.