If there's no indication, it can wait.

Land Rover sold these cars with gearboxes "sealed for life".

ZF's own recommendation however is to change every 150,000. 2015 Range Rover Autobiography 4.4 SDV8

There is so much to be found on this subject that it is probably correct to simply go with what the manufacturer says….which is 100k km (60k miles) or 8 years.

https://aftermarket.zf.com/sea/en/aftermar...il-change/

The whole idea of “sealed for life” just never made sense for something that relies on oil to function, and is supposed to last a bit longer than 60k miles.

You’re probably right that I could just drive to Prague and do it later, but given that it could be at double the manufactures recommended interval (it may have been done but I have no documentation of it… so won’t know until they get into it), I’d rather not put that kind of mileage on it.