Cable OK flying between rafters?

or need i put a batten there?

I think it'd be fine just clipped to the rafters, but perhaps someone who actually knows the regs will come by and let you know more reliably soon.

no problem at all

NT

I do know one thing thanks to the law of Mr Sod, if you do not allow a bit of extra on a run, something will come along and mean the whole run will need to be done again when the thing is just a little too short when an end breaks off or needs to be moved.

Brian

Clipped is nicest - but in reality (and I'm sure Adam will have something say) it's usually just dropped on the ceiling or draped over -

(OP) If the rafters are devoid of ceiling below (totally open) you could push some trunking over the rafters and sling the cable in that, or if you're actually wiring it, push it through some conduit and just clip the conduit at each end - that will be a first class way to do the job.

Me: I have screwed a bit of 2x1" across the top and sat/clipped the cable to that.

whole run

You "lose" it along the run, any changes in direction are lazy and go wider than they need to but still remain neat. You have a generous 6" of striped cable(*) in the box behind any accessory, you have used 35 mm deep boxes haven't you?

(*) Well for sizes up to 4 mm^2.

Yup, that's fine. Its out of harms way, and supported at regular intervals.