Since the UK is no longer part of the European Union, i dont know even know if the same rules and restrictions for autonomous driving are in place between the two regions. Apart from that i can imagine that it requires extra training and data for RHD Countries as they are quite rare. Simple Solutions like inversing the camera input can not work because all the signs would be inverted too which makes things difficult to comprehend and thus need extra training for RHD. Im no expert in this but i can imagine this being the reason. Fingers are crossed that RHD support will also make its way to UK and general FSD Support its way to Europe