The ‘regulated by the BSB’ and the usual boilerplate bit about confidentiality/privileged info etc.. part suggests it might be but the sign off seems a little basic and thin in detail and the absence of any reference to Legal 500/Chambers and Partners within it seems a bit odd, yet LinkedIn is in there. Most chambers have a boilerplate email sign off which is far more detailed than that. Plus no direct dial to his clerk seems odd.
Wouldn’t expect him to put his mobile on there although many silks do.
Edit: plus the LP thing is a bit weird. It means his email address must be lordpannick@… which seems like a ridiculously pompous email address to have and meant he would have changed it when he was made a Lord -although tbf some people do add KC at the end of their email address when they take silk, although I think it looks wanky personally