Niall,
So the whole unit is just switching off entirely? If so I'd be suspicious that the quad-lock connector isn't fully in. If you're not handy, I'd suggest leaving this to the dealer as it's _very_ easy to break the clips holding on the fascia around the RCD/RNS area.
Having said that, you are not confusing this issue for the TP function whereby the radio will interrupt your music for traffic announcements (which we don't actually use in Australia properly) if you're turned TP on.
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