In Most cases you cannot build up any No Claims Bonus by being a named driver on someone else's policy. Check for the exceptions, there are a few. This could be an advantage for spouses or young drivers.
Drivers found driving without insurance can have their car impounded or even taken away to be destroyed. But even worse than that, should you have an accident, you caould be liable for that total amount of damage. And you also risk, getting a criminal record, should you be stopped by the police.
Voluntary excess is an agreement you make with the policy provider to pay a higher percentage of excess at the time of an insurance claim. This also means it would be unlikely you would make a claim for a small amount of cash and risk losing your no claims bonus.
Even if you have had a poor quote from an insurer previously, try them again as sometimes their pricing structures change.
