I'd been having a few issues recently but never pieced them all together until last night, thanks to my brother insisting I double check my IP address. Turns out my public IP address changed at some point recently, the main reason I hadn't twigged was because my TBB Ping monitor graph was still working, yes it has showed some downtime in the early hours recently but just assumed it was Virgin. But it transpires that VM has changed my IP and my old IP which someone else now has was still responding from pings.
Another reason I didn't realise is because pfSense hasn't sent a notification email, and I'm not sure why. I have notifications setup and they work, I get notified on a reboot, and if I hit test I get a notification.
Done a bit of Googling this morning, and that research suggests so long as I have notifications setup then I should get one when the WAN IP changes, any ideas why I didn't?
PS. I'd had the same IP address since April 2018, apart from if I use router mode on the SH3 or a different router in modem mode.