Used to describe a man/woman who has a very attractive body which is let down by a face that looks like a mug shot.
This is a word play on two popular TV shows in the UK, Baywatch
with muscled and tanned bodies and crimewatch a TV show highlighting criminal activity with many mug shots of scary looking offenders or wanted criminals.
See also BayCrime
She has a body like baywatch and a face like crimewatch.