If i added my other half onto my insurance it goes up loads, he's 29 but has 11points (dont ask!) either way it doesnt help and he has full NCB and been driving...forever (11years) and yet i cant get insured on his Lexus IS200, his insurance company wont insure because im under 25. Different things effect it in different ways. I found having my home insurance with Direct Line helps as well.
But no way should you lie on insurance, its not worth the risk in the long run. If you cant pay it out right, just pay it monthly, i know you pay a little bit more back but if it means you can have the car so be it. I pay £41per month with Direct Line, 4yrs NCB and driving, lives on a drive and im 23. But i am a girl which kinda helps.