If you can prove that you don't own the car there shouldn't be a problem. The registration document states that that the registered keeper is not necessarily the legal owner.
Just get paperwork from your mum to prove it.
The friend in my adversity I shall always cherish most. I can better trust those who helped to relieve the gloom of my dark hours than those who are so ready to enjoy with me the sunshine of my prosperity. – Ulysses S. Grant
The friend in my adversity I shall always cherish most. I can better trust those who helped to relieve the gloom of my dark hours than those who are so ready to enjoy with me the sunshine of my prosperity. – Ulysses S. Grant