This is my thinking also Mike, if I had found him in a work house or somewhere in 1891 then I'd be sure it's the same person. But this has filled me with doubt.
Also, i looked some more on the newspaper website and found this:
EXTRAORDINARY ASSAULT BY A LITTLE BOY. - At the West Riding Police Court, Pontefract, on Saturday, Charles William Poskitt, elevens years of age, son of Charles Poskitt, collier, Castleford was charged on warrant with an aggravated assault on Sarah Ellen Whittington, aged six, the daughter of Richard Whittington, collier, on September 17th. The prisoner threw the poor little girl down a stone heap and nipped such pieces from her body as to cause very dangerous illness and which still keeps her confined to her room. The prisoner was remanded till Wednesday to the workhouse for medical and other evidence.
My Charles William Poskitt's father was William Poskitt, not Charles... Another indication this might not be the same kid... Except I can't seem to find another Charles William Poskitt (b1875) with a father called Charles anywhere?!