It died just as I was firing up the VM having got the Windows scammers hooked – they were so interested that I got passed to a supervisor and they then tried twice to call back after the handset died. Strangely the conversation started off with them saying I had a problem with my Apple Mac, so presumably Apple users are no longer immune from this (I was disappointed how quickly they worked out I was on a Windows PC, though if I’d not wasted time on that I might have got them to try hacking my VM).
Regarding the phone, it seems to trickle charge the handset batteries, so killing them – had kind of given up bothering to replace them as I just use my mobile for anything important, and get very little other than junk calls on the landline.