Rolls Royce battery died, is a mobile service actually safe for these cars?

My Ghost has been sitting in the garage for a couple of weeks with a battery that keeps dropping charge, and the dealer quote to replace it was honestly eye watering, plus they wanted the car for most of the day which I can't spare right now. I started looking into whether a mobile service could handle something like this properly because I've heard these cars are fussy about battery registration and the wrong unit causes all sorts of electrical confusion. A neighbour mentioned he'd used Rolls Royce battery replacement ByBattery Zone UAE for his own car and said they came to him, though he couldn't remember much beyond the fact that it worked out fine. What I'm unsure about is whether a mobile technician can really do the registration properly on a Rolls or if that's something only the dealer can handle. Has anyone here had a battery swapped on a Rolls or Bentley by a mobile service? Did it all work out or did you end up with warning lights afterwards? I'd rather hear from someone who's actually done it than take a chance on a car like this.