Sorry I've been quiet for the past few weeks - holiday and work both eating my time.

During my travels, I think I've found why AF following wasn't working for me while I listen to MP3s. Try this:

• Tune to BBC Radio 4 in Cambridge, ensuring that AF Debugger shows an active display
• Drive north for a few hours
• Note that before you reach Glasgow, the player struggles to find signal on any alternatives
• Eventually, it will tune in to BBC Radio Scotland instead of Radio 4 (and it doesn't seem to check the PI, but that's already reported)

If, however, you re-tune somewhere near Penrith (by knocking the stalk forward then back, for instance), it works properly.

What I think is happening is that when we re-tune to a new station, we're not picking up a new AF list. So in a linear country, with transmitters A, B, C, ... where each one advertises its immediate neighbours, if we travel from B to C, we'll still only check A B and C, even though we should be sampling B C and D. Which means that when we lose sight of C we will be unable to find any decent signal.