I don’t dispute that any of the anecdotal accounts here and elsewhere might be true.
But I don’t think they should be assumed to be typical.
On average, as a generalization to which there were certainly exceptions, I would say there were a lot of co-ed schools in the UK where only the boys ever received C P.
My own 1950s Yorkshire primary school was a case in point: boys were quite often spanked or slippered, in front of the class.
The girls got to watch this but never, ever, received it themselves.
I’m not saying that was absolutely typical either.
But it clearly wasn’t particularly unusual.