We still haven't seen any docs. However, OP can we go back pl:
The car was seized because the bailiff had a warrant of control in the name of a specified person.
This was not you but, according to you, a relative.
But the warrant doesn't point to the car, only a person. It's therefore a reasonable assumption that the car was specified in the enforcement docs(PCN etc). They have acted on this assumption and then you, who are not the person named in the warrant, approach them and tell them you are the owner of the car which must therefore be released.
As others have posted, they would normally do this immediately, but so far not in your case. If you are the legitimate owner of the car then they must release, their actions - although legally permissible when they clamped the car - become unlawful once you have produced proof. But as you're not the debtor their only issue is whether you are the owner of the car.
With respect and IMO, a SD/WS has nothing to do with your situation. Firstly because TEC only deal with enforcement matters and this is NOT an enforcement matter, it's the Tribunal's and Courts Act -
https://www.legislation.gov.uk/ukpga/2007/15/schedule/12Secondly, you aren't the 'owner' for enforcement purposes(this is your relative) therefore IMO TEC would disregard anything submitted by you because you're a stranger for their purposes.
You don't have to continue with the bailiff, you could call the police if they would be persuaded that you are the owner.