Does a car need a warrant of fitness (WOF) when it is sold?
Generally - Yes !
When selling a vehicle it should have a warrant of Fitness that is not more than one month old.
But you can sell "as is where is" without a WOF
You can sell a vehicle without a WOF, but you must have a written agreement with the buyer stating it is bought "as is where is".
(If the Vehicle requires a Road User Charge (RUC) license (diesel vehicles), the Seller must still provide a current RUC licence even if unregistered, unlicensed or unwarranted).
Here's some suggested wording you can use if buying and selling "as is where is".