Possibly – but more likely, it was just understood that corporal punishment was less useful and less effective with girls regardless of the school they were in.
It might have been less effective with 10% of girls than 100%, but unless girls were treated the same as boys how would you know. Those 10% of girls might be the same 10% of boys that it’s not effective on.
In the years leading up to abolition, more and more education authorities dropped CP, post abolition the behaviour of boys didn’t deteriorate, or escalate over night, there were reports when the House discussed the abolition for private schools over a decade later, behaviour had improved in some state schools without the threat or use of CP.