Thanks, Jock1e. No, the letter was not one of their usual automated junk mail letters [I've recieved loads asking me to change to one of their broadband packages over the years], but addressed to me, by name. Usually I don't open them ... and are binned.
I'll check out their forum you have provided a link to.
I will have to 'bite the bullet' and go mainstream or perhaps upgrade my 1GB dongle to a 3GB one, to compensate for loss of dial-ip.