Bedford MJ Range Fire vehicle question

Does anyone know anything about the vehicle in the attached photo?  It’s Bedford MJ onto which has been mounted a body similar to those carried by German civilian Magirus Deutz mercury 120 fire trucks. I’ve been told that one very like it was used on Haltern Ranges in Germany and that it may have been manned by troops using the ranges, rather than by Army / Defence Fire Service personnel. The person who provided this information last saw it at Sennelager in the early "Noughties" when it was in LAD Workshops.



One of these vehicles was sold some years ago by VEGEB - the Federal German agency through which some surplus British military vehicles in Germany were disposed of. It, or one very like it, subsequently appeared at military vehicle rally held at the Fallingbostel military museum.  Photographs taken of it there and subsequently posted on the internet describe it as an ex-Army Fire Service vehicle.

I’m interested to know more about its history and deployment. I suspect that it was a one-of local conversion but it would be good to have confirmation of this.  I would also be very interested to see any photographs of it during its service life.