Hazet has a nice vacuum coolant filler (4801-1). You can get either a set of 3 rubber cones with it, or application-specific adapters. I'm allergic to "universal fit", and besides, the 3 rubber cones would make me feel like I bought it off of Aliexpress.

Of course finding out *which* application-specific adapter fits a 2015 Flying Spur online is near impossible. Normally I like a good internet hunt, but this one beat me.

I finally broke down and fired off an email to Hazet. Turns out is *is* online (if you know where to look):

https://www.hazet.de/de/downloads-anwendungen/kuehleradapter

(I tried to dump a screenshot here, but it didn't work.)

While I've ordered a 12A, I haven't actually gotten it yet, so I can't personally confirm the fitment. Just thought I'd save anyone else the trouble of making a query with Hazet.