Whilst I'm no fan of unrestricted CCTV I don't see this as being a step towards tyranny.
Garages already have cameras in place to stop fuel theft (filling up and driving away -- one tankful can wipe out a day's earnings as the margins on fuel are low - why do you think forecourts also sell sweets, newspaper, groceries...).
Whether they should act as unpaid agents of the police in tracking the uninsured is debatable but uninsured driving is not a victimless crime.
If you're uninsured it's probably because you and/or the vehicle are a poor risk and more likely to get into an accident.
If you do get into an accident then innocent people could be disadvantaged (through injury and loss/damage to property) - who will pay to help them get back to the state they were in before? insurance companies - not if you're not insured (they're weaselly enough when you are!).
So the victim either loses out completely or, if they are very lucky may get a pittance from the criminal injuries compensation scheme - paid for by the taxpayer.
If the victim's car is damaged - they have to claim against their own insurance - losing "no claims discount" and getting higher premiums next year [and don't think about shopping around, the insurance companies pool claims data]. The insurers recoup this lost cost through putting up premiums for all of us.
Taking the uninsured driver to court may get him/her a conviction (more costs to the state/taxpayer to keep him/her in gaol or trying to recover fines) but precious little help in civil recovery for the victim.
The uninsured are a burden on everybody - I have no sympathy for them
In this case it seems a fair use.
Finally, since this is Slashdot, if you want a free market response - nobody is forcing you to buy petrol or drive uninsured - it's your choice; the garage also has freedom to mandate terms of sale.