Scruffy Black Tape Along Base Of Windows

[daddypatches]

I appreciate this is not high on the list of problems associated with this car (I know, I've had a few recently!) but this car comes with what looks like black tape along a silver strip at the base of each of the door windows. Mine is looking rather shabby and could do with being replaced as it's bringing down the rest of the car.

Has anyone been able to source this stuff and fitted it? Anyone know where to get it from? Is it easy to replace or best left to a professional - I've read on here somewhere that Lexus wanted to charge £50 per window to replace it which is quite frankly ourageous, but in line with my experience of them!