Grohe vitalio joy 260 shower rail too long

[Craigsg]

We've just purchased a grohe vitalio joy 260 not realising the shower riser rail is not adjustable and it is too long/tall for our shower it hits the ceiling. Grohe say you cannot cut the rail/pipe and must purchase a smaller one off them.. has anyone cut one shorter before and been ok?

 

[Ben-gee]

No, but put up a picture of the relative mating parts - I have successfully done this on what I imagine to be a similar set-up on a Hansgrohe shower (there was only 1mm of coverage so the cut had to be executed and finished extremely carefully)