I want to lay some 22mm speedfit (the coiled kind) from one location
upstairs to another. This needs to pass under a room whose floor I
really want to avoid taking up. Fortunately, the joists run parallel to
the direction I want to go (I can see them in a cupboard downstairs
where the ceiling has been omitted). It should be practical to run the
pipe in at one end and push it all the way to the other, running between
a pair of joists. I could probably clip it into place at both of those
ends. But in between, a distance of maybe 3-4 metres, it would be
floating loose. Is this permissible, or a horrible bodge? I've never
worked with Speedfit before.

The house is of conventional early-90s construction.

Pete