Sue,
If you've spoken to your current insurance company and they are not ready to put your son on your insurance policy, then there's nothing you can do about that, unless of course you change insurer. Short term insurance is usually difficult to obtain for new drivers who are under 21 and don't have at least a year's worth of driving experience but since you are looking for 1 month car insurance and your son has already passed his driving test, you can try eCar Pay As You Go Insurance. There shouldn't be any problems for your son to get a month's insurance cover under this policy.
