What connectors?

[RoyMi6]

Needing to fit this shower: https://www.showerstoyou.co.uk/uploads/documents/Triton_aspirante_installation_guide.pdf

Doing the first fit of the bathroom (my plumbing mate is out of town) but I need to get from a single cold feed coming vertically up the wall into this unit.

I'm thinking I just want this to attach to the pipe inside the wall:
http://www.screwfix.com/p/p803wp-2-wall-plate-elbow-15mm-x/92934

When presumably it would make sense to use a straight connector with one of the compression fittings removed to screw directly into that thread...
http://www.screwfix.com/p/straight-couplings-15mm-x-15mm-2-pack/95828

Also, this allows me to attach a bit of pipe that I can have sticking through the plasterboard and wet wall...

Then just a 15mm elbow outside the wall and inside the shower unit to get it lined up?

Missing anything?

 

[Telecaster]

Only had a quick look at the shower instructions, but does it not say that when the shower is fitted the compression elbow will sit slightly inside the wall hence leaving enough gap around tiles/whatever to make adjustments? If that is the case then a surface flush elbow will stand the shower unit proud as it won't go back far enough.

What do you have in the wall at the minute?

 

[RoyMi6]

There's no wall at the minute!

Old bathroom ripped out to the studs.

Oh, also, the mounted elbow I was planning on screwing into a dwang behind the wall. Like right at the back of the wall (which is maybe 2 inch deep)