If your vehicle has been seized and put in a police compound then you will be given a seizure notice at the point the vehicle was seized by the police or sent a seizure notice, by post, from your local police force.
In most regions you will need to visit the designated Police Station with the seizure notice, driving licence, proof of vehicle ownership, proof of address (two items of proof of address needed), a valid MOT certificate, valid road tax and proof of valid insurance that covers you to release the vehicle from impound. The Police will then stamp your seizure notice. You can purchase impound insurance from Acorn Insurance.
You then need to take the stamped seizure notice to the compound where the vehicle is being held. You may need to show some or all the documents listed above. You will then need to pay the release charges which comprise a one-off release fee and a daily storage charge. Please be aware that fees are set by the government, not the Police.