It is not strictly true that you will receive a ban through totting up if you get to 12 points. This is a matter for the courts to decide. You can raise your mitigating circumstances and state the reasons you need to keep your licence and then the courts will decide what to do with you. They may just give you 5 points to take you to the 11 or they may give you the full 6 but allow you to keep your licence.
As for the offence though I am afraid it is complete. It is your responsibility as a driver to ensure that you are fully legal.
Damn unlucky though and you MAY have a civil case against the insurance company to claim any fees.