I had a chance to properly trial the shark fin aerial today and I'm pleased to say it passed with flying colours
I selected DAB station (Smooth East midlands) here in Derby and then drove 45 miles into the peak district through all sorts of hilly terrain and reception remained perfect at all times with 5/5 bars showing all the way there and back.This would have been unthinkable with the windscreen aerial,it was hit and miss even in certain parts of the city,especially at night and when the nav was in use.It was well worth the investment,I don't listen to anything other than DAB+ now.