Proof of NCB?

Years ago it was a real arse to prove your NCB to a new insurer - you had to phone your old one and pray thyat they would post the proof through to you and you passed that on to your new insurer,

Nowadays they all share info on you - and can quote accidents and “incidents” (where you didn’t end up claiming but still get a black mark…

So why are my insurers asking for proof of NCB? Surely they share this as well?

Any thoughts…?

Could be due to Data Protection - whilst they may share data on accidents, due to (apparently) be trying to prevent fraud, NCB’s aren’t part of this, and therefore aren’t shared?