Can insurance companies find out if points are not declared?

[Mark-hmvi7]

Hello,

I already have 3 points my insurers know about (Liverpoool & Victoria)

I've just got another 3 points which is going to affect my premium.

If these additional 3 points are not declared will it totally invalidate my insurance?

If I don't declare can they find out themselves about them?

Thanks in advance for any advice.

Mark