You can add your mum on a policy as a named driver, so the policy is in your name, you build up the NCB but by having a woman on the policy too it will bring the preium down.
My Rangie was £825 fully comp at my renewal (9 yearts NCB), so I added the Mrs to the policy as a second driver and it came down by over £100!!
By the sounds of it then getting my mum to insure it and me as a named driver is the best yet.