Impounded car insurance is a specialist policy designed for cars which have been seized by the police and impounded, because the driver was suspected of driving it whilst uninsured. They are normally available for 30 days (the minimum period the police will accept) or a year.
There are very few insurers which will provide them.
No. Mainstream insurers will not cover cars that are currently locked in a pound. You would be under an obligation to inform the insurer of this and if you were facing a charge of driving whilst uninsured you would have to tell them about that too. Failing to do this would almost certainly invalidate your insurance and could also lead to criminal charges against you.
Yes, once a car has been released you can get quotes to insure it in the normal way. However you would be obliged to inform the insurer of any pending prosecutions as well as any past accidents or convictions you have had.
Yes. Even if the car was driven without insurance accidentally it is looked upon by most insurers as a riskier proposition and so premiums are higher. However you can mitigate this by buying a shorter term (30 day) policy.
You would have to balance the cost of a policy against the value of your car since if you don't get it released it will be disposed of and you will get nothing back for it, although you might still have HP or other payments to make on it, plus the police may charge a disposal fee of £75 upwards.