Blimey

So I'm riding home and things are going OK, except I can't work out why Supertramp keep coming round on the iPod.  

I'd been following a lady in a Corsa for best part of a mile round the Isle of Dogs.  She slows down a bit and starts indicating right (irritatingly in that order).  As I decide to go past her on the inside, she changes her mind and rapidly pulls into the kerb, still indicating right.   

Having used ninja braking and ESP to avoid a horrible accident I knocked on her window.  She had a nice face and was very polite - but could not see that she had done anything wrong, which made it all the scarier.