Child abuse is ubiquitous.
On-street grooming by gangs has not yet been shown to be.
That is the crime I have been discussing.
Let us just consider one crime at a time.

Engage deals with all types of abuse.
Their biggest case as of last October was a dance teacher abusing his pupils.
They also deal with familial abuse, internet grooming and solitary playground prowling perverts.
That is where the irrelevant 80% comes from.
The only evidence so far produced on street grooming by groups is from the Midlands and the North, and is all BPs.