Dect phone on HomeHub

I have a DECT phone registered to my HomeHub which worked fine until recently when it stopped ringing(it shows the call briefly and stops)I have changed the phone and the Hub but the fault remains.
Both BT Talkline and the land line are set up to ring BT Hub Phones and Phone socket. Does anyone know anything about this?

Does the DECT 'phone plug directly into the homehub or is it via a small adapter pod?, I had a similar problem with the 'phone not ringing (different setup though, although it is setup to ring the 'phone for incoming PSTN and voip calls). The 'adapter pod' contains a ring capacitor and the do occasionally fail.