Flying Spur transmission fluid service, is it really lifetime like they claim?

My 2015 Flying Spur is at about 70,000 km and I keep hearing mixed things about whether the gearbox fluid needs changing at all. The manual hints at lifetime but I have owned enough cars to be skeptical of that word, especially in this climate where everything degrades faster. I found https://gearboxrepairsharjah.ae/brands/bentley/ while digging around for answers, but I am not booking anything yet. Has anyone here actually done a transmission fluid service on their Bentley and did you notice any improvement in shift quality? Also does anyone know if these boxes need a specific procedure that only a specialist should do, because I do not want someone treating it like a regular automatic. I would rather maintain it properly now than face a rebuild bill later.