Last night my Amundsen + dumped all the DAB stations whilst I was stepping through them on the way home.

 

The names were still displayed but the no signal graphic lit up. I still have FM/AM functionality.

 

Has anybody else had this - and how can I get them back?

Sounds like you lost the DAB signal. Not sure if you can on the Amundsen + but on the Columbus you can see the DAB signal strength in the setup menu.