Location of reversing switch 2.2 HDi peugeot boxer 2004?

Can anyone advise exactly where the reversing switch is located on the Peoguot Boxer 2.2 HDI 2004 engine please. I assumed it was on top of the gearbox but can't see it anywhere then I thought it may be via the gear lever on the dash but that's difficult to get to. Has anyone any ideas, it's got to be there somewhere maybe hiding behind a pipe or something so I just need to be pointed in the right direction. Thank you

Phil AP
March 2012