Columbus DAB/FM swinching - or not.....

My previous Octavia had an Admusen which was excellent at switching to FM when it lost the DAB signal, so much so the only reall way to know it had was to look at the screen. My late 2017 Superb's Columbus is very poor - somedays it works perfectly - seems to be if I have waited outside the house where there's no DAB until it clicks over to FM then it does so happily until it is switched off. However most times it just refuses to do so. Has anyone had a resolution to this issue?