A mechanic (or anyone with a multimeter) could quickly check the efficiency of your alternator by checking the voltage of your battery while the engine is running. A new alternator is one of the cheaper replacement parts on most cars(and requires very little labour to fit).
If your radio has RDS, and you've got traffic reports turned on, it will automatically switch to an appropriate channel when a travel report is broadcast. For example, let's assume that you're driving in Suffolk and listening to Radio 2. If BBC Radio Suffolk puts out a travel announcement, you radio will automatically switch over to that station for the duration of the announcement. (If you're within range of the BBC Radio Essex, Cambridgeshire or Norfolk transmitters, they'll also make your radio change channels when they broadcast travel news).
If you've got travel announcements turned on, there will be something like 'TA' or 'TP' displayed on the radio's screen. You need to look for a similarly labelled button to switch the function off.
Chris