I've done some searching and can't seem to find any garages that specialize in this make of vehicle in HK.
As you probably already know, it's not a good idea to try to service or repair a car at a garage that doesn't focus on a particular brand. They won't have the vehicle specific diagnostic tools and if they are not familiar with the car, it can be a steep learning curve to repair what might be a simple fix for Jaguar expert (and you pay for the hours...).
A mate of mine is a mechanic at Toyota and he warned me off of using a generalist mechanic on a BMW --- he said that what they sometimes will do is replace BMW fluids with non brand-spec fluids (which are quite a bit cheaper) because a) they don't know any better or b) so that they can come in with a more competitive quote. Doing so saves money in the short run can damage the vehicle.