Keyless door unlocking / proximity key issue

[sjb]

Hi all

MB XR5 had first (15,000km) service this week and since it came back from the dealer, the proximity key no longer unlocks the car when you pull either of the rear door handles. Both front doors (and the hatch) still work as normal, and the rears will trigger if you pull them after you've already unlocked the driver's (its set to dual-stage unlocking, to unlock only the driver's door first), but trying to trigger unlocking of either rear door wont work anymore.

There's nothing in the settings (I did have to re-program most of the personal setting when I got it back, telling my they probably disconnected the battery or the system during the service) and I spoke to the dealer on the phone who suggested I "bring it in to look at", so I wonder is anyone aware of this issue and how to fix it? If you use the buttons on the key like a car without proximity keys, everything unlocks as it should.

As I said, the proximity key has always worked on every door handle in the year since I bought the car, until now...

Thanks in advance for tested solutions, or your best guesses as I suspect the dealer may just shrug their shoulders if a quick and dirty reset doesn’t fix it...!