There has been some disagreement about the level of checks performed by add/subtract and multiply/divide. Up to Iris 1.12, the behaviour was not consistent between the two groups of math ops (add/subtract had more strict coordinate matching checks than multiply/divide).

This PR changes the behaviour of multiply/divide to be consistent with add/subtract: #2498

This was merged and released in Iris 1.13, but @rcomer has raised concerns that the checks may be too robust, and may need some deeper thought before we decide on which consistent behaviour math ops should follow.

See here for use case

Acceptance Critera

• Agree what coordinate compatibility checks should be performed for add/substract/multiply/dividing cubes
• Agree whether to allow users to "turn on/off" different behaviour