deano wrote:
I got a couple of male 90° 22-15mm compression couplings to fit onto
the end of the pipes and up into the valve hot and cold inlets. This
way the pipes can go straight through the wall at a right angle.

When fitting the 90° couplings to the valve, how do I make them both
point in the correct direction (i.e. at right angles to the wall, so
they meet up with the feed pipes) when they are fully tightened?

Assemble everything before you tighten up. Use a spanner or grips
to hold the things while you do them up.