> Maybe making a regualr speeding fine a life changing amount rather than the negligable sum it is now would improve people's behaviour, raise some much needed revenue and save a few lives too

The fine is negligible if you are well off. It isn't if you aren't. If you get points (for SP-30), the increase in insurance is about £300-400. So the actual cost of the fine is closer to £400-500 which is the rent for the month.

There has already been talk of making the fine be adjusted to how much you earn.