Kes
I'll Decide ...
I'll always consider advice from yourself @JamesL as you know mate, but my opinion with this particular challenge is that there was no force or endangerment evident.Not strictly true.
If opponent safety is endangered w/o excessive force it can still meet the threshold for SFP, hence the endangering safety OR use excessive force OR brutality.
Although in this scenario force is most certainly a consideration as to if safety was endangered or not.
Had both players been travelling towards each other at speed or some such scenario then the outcome (both physically and in terms of Law 12) would/could have been different of course.
I'm just opposed to the misguided idea that some referees (and most players) have that equates to "Studs showing - has to be red" which is of course utter rubbish.