Greetings from Indonesia
For CVT, it will be good to replace the fluid based on how often the car is used and where do you live. I live in Jakarta, Indonesia where traffic jam occurs all the time and proceeds to maximum wear of the CVT fluid. I usually change the fluid after 25.000 km drive. Recently I’ve broken my CVT of 30 series alphard because of a leak from the drive shaft oil seal without knowing that the automatic fluid already spilled.
I think alphard users in the UK should learn about maintaining CVT from the mechanics in UK, because most of CVT ( either nissan, honda or subaru) is almost the same in terms of mechanical theory, and i cannot give exact interval of CVT fluid changing because i don’t know environment in UK. Fluid changing (whether it’s for engine oil or transmission oil) as we know is affected by weather, dust, how long the car will be used, how hard the terrain the car will driven to, etc. so if you following the manual book, which is made for japan environment, it will not so accurate.
cheers