DART tags — valid?

Cheers fellas, there’s always been a tenner or so credit on the account, which was transferred from the old account to the present system when I registered my car registration, I figured if I ever needed to pay for the crossing in a truck I could go online and change the registration number.
I’ll have to take a look at my other tag accounts (Tyne tunnel etc) and either get them switched to the car, or closed