With the current versions of iPod Classic and Nano, the backlight on the iPod remains on continually during DAB or FM sessions even if you manually turn it off in iPod settings. Not only does this dramatically reduce the battery life, it can also damage the screen as it has a static "Robi by ROBERTS" text in the centre of the screen which will eventually cause a 'burn' of this image on the screen.
Roberts technical support admitted this is an issue with these iPod versions but have decided not to advertise the fact, rather they simply advise poeple who call them to return it to the supplier and attempt to get your money back. Not very satisfacory.