Talking to a client yesterday who told me his nearly new BMW was suffering from a flat battery. He took it to the dealer who advised the battery was weak.
He asked them to change it without a price check and unsure if it was a warranty item (it wasn't) and they charged him(no pun) £450.
They said it was £120 to test the old one + new battery + fitting and £120 to test the new one.
Writing this it still sounds unbelievable, but no reason to doubt him.
You know it makes sense! 
