Location of speed sensor on a citroen c5?

Hi all, a code reader has just read that my speed sensor A has malfunctioned on a Citroen c5 1.6l diesel 2008 and I was wondering if anyone knows the location of this device on the car, the drivers side or the passengers side and is it on the top or bottom of the gearbox????
Many thanks in advance
p.s. I have googled it and can't come up with a definite answer.