When the sale of .co.uk domain is made due to the "unique" nature of domains the seller enters into what is known as a "constructive trust" and must act in the interests of the buyer and that means not reducing the rights of the .co.uk by registering the .uk for themselves (if the right exists).
So if not registered before the sale agreed and it is not mentioned specifically in the contract, the seller should not expect to register the .uk for themselves after the sale is agreed and then try to make double money.
As the seller could technically register the .uk domain and break the trust, the seller would be liable for damages to the buyer.
I'd have to disagree with you there, Stephen.
This is the Sedo contract, the one all buyers sign up to when they agree to buy a name...
2. Purchase Object and Purchase Price
The Purchase Object of this Purchase and Sale Agreement of 06/14/2014 is the Internet domain name example.co.uk, and when included by the Seller as indicated on the Make Offer page, the related Website.
The Purchase Price shall amount to £650.00 GBP including any statutory tax that may be incurred (for instance VAT).
3. Warranties and Representations
a) The Seller guarantees that they are the owner of the aforementioned Purchase Object and may freely dispose of said Purchase Object. Furthermore, Seller warrant that the Purchase Object is not encumbered by the rights of third parties and that to date, they have not received any warnings of potential litigation or preliminary injunctions against the Purchase Object that have not been disclosed to Buyer.
b) The Buyer understands and agrees that it is their sole responsibility and duty to perform all necessary due diligence before entering into this agreement to buy the Purchase Object, including research of fitness for particular intended uses, trademark clearance,
or anything that could inhibit their future use and enjoyment of the Purchase Object.
c) Buyer and Seller shall be liable to each other only for damages that are based upon their failure to perform the necessary steps to complete this transaction, intentional wrongdoing or gross negligence and shall not be liable for claims seeking consequential or punitive damages.
- Rob