In message , Bob Henson
writes

However, it might still apply depending what other devices the OP
has attached already. One old wired telephone for use in power cuts, two
DECT bases (if he hung the second one on separately), a modem/fax
machine and Robert is your Avuncular Relative.

Thanks, guys, for all the comments. Two entirely sets of four now
plugged in and working. No, we don't need eight, but at least that
keeps the handsets charged.

Non transferability is unlikely to be a problem. Not something we ever
use. We do have an old style phone for power cuts, but that is the only
time it is ever plugged in. No fax machines, or anything like that.

To be honest, we only want multiple phones because we can't hear them in
other rooms! The walls here are thick, solid granite, and modern phones
are not as loud as the traditional ringing phones most of us grew up
with. Could just be that we're a pair of deaf old gits :-)
--
Graeme