Need a Rolls battery specialist near Business Bay, dealer is too slow

My Dawn battery is on its way out and I have been trying to get the dealer to book me in for over a week now, they keep saying the earliest slot is next month which is ridiculous for something this simple. I cannot risk the car dying on me in the meantime so I am looking at alternatives. Has anyone used a leading Rolls Royce battery specialist near Business Bay, or anywhere close by like Downtown, that they can actually vouch for? I am not trying to cheap out, I just want someone competent who will use the right battery and do the registration properly without me waiting weeks. Also, does the car need to be with them for a full day or can it be done same day if I drop it in the morning? And if anyone knows whether these independents use genuine Rolls batteries or aftermarket equivalents, that would help me decide because I am a bit paranoid about anything non OEM on this car.