Hi Welcome to JustAnswer. My first response will follow shortly. Please feel free to follow up if anything is not clear

You can appeal to the Police under Section 102 of the Land Transport Act but only on certain grounds.

Possibly this may be relevant

d)the owner took all reasonable steps to prevent the driver from driving the vehicle; or

(2)An appeal under this section must be set out in a statutory declaration and lodged no later than 14 days after the date on which the vehicle is seized and impounded.

Yes, because the police will say it is his. I would assume it belongs to both of you, but if you qualify, it is worth trying on the basis that while it was jointly owned, you did not permit him to drive

The certificate of ownership is not evidence as to who owns the car, although it is often used for that purpose. If it is the family vehicle then it is relationship property and jointly owned. i expect you share the costs. The police could be difficult about this for this reason, but its the only way to get the car back.

The statutory declaration is dealt with by the police, although there is a right of appeal to the court. It costs nothing to fill out the declaration so you might as well try. You dont need to go to court for the declaration though

Tell the police if you need the car to take family around-kids to school etc-that will help, and make sure you tell them your partner was not permitted by you to drive.