Any question answered...

I just had a nasty altercation with a van driver (P11 SBJ) who nearly squashed me by changing lanes (into me) whilst on his phone and without signalling. Remonstrating with him, calmly, resulting in him using his vehicle to try to run me and another cyclist off the road.

Is it worth reporting it? If so, who to? I have the other cyclists details...

If there's a witness report him to Police.
I'm sure I've read about a similar case on here and they caught up with the guy some time later and he was cautioned/charged.