I was involved in an accident that was my fault and I had not declared the 3 points on my license, when the insurance company contacted me about the accident and they asked if I had any points, i said yes and they said I should of told them when the points were added (i took policy before gaining points). They just said to me that they needed to adjust my premium accordingly and that was that. But I suppose it just depends on your circumstance... I would keep just keep quiet if I were you, just like the time I had an accident which was not my fault but my MOT had run out by 1 day... its up to you...