You may have a valid Special Reasons Argument.
"Special Reasons Arguments
It can sometimes be argued that, whilst you are technically guilty of the offence in question because you were uninsured at the time you were driving, you have Special Reasons in relation to the circumstances in which you were driving, namely that you were driving under the genuine misapprehension that you were insured at the time. If you successfully argue that there are Special Reasons then the Magistrates have a discretion not to impose penalty points. In order to argue Special Reasons you would need to support your argument by giving evidence on oath and it is preferable to provide documentary evidence to the Magistrates in order to support your argument."
http://www.pattersonlaw.co.uk/No-Insurance,-Pe rmitting-No-Insurance.php