I got caught just over 10 years ago but I didn't know that you had to notify the insurance company. On my renewal notices now it lists all my previous claims, windscreens, etc. and it still lists the SP30 so I'm pretty sure that they are notified by the DVLC. Whatever happened to the rehabilitation of offenders act?
My licence had the old postcode so after three years I sent it off for a free address change thinking that the 3 points would be expunged. I now know that you have to wait 4 years, and pay another fee (fine) to have them removed.