Would this be classed as ABH?

[Emz2019]

Would it be classed as ABH if your baby is sat in his bouncer chair in your living room and some thug throws a very large brick through your window and flying glass cuts your baby in multiple places? Even if the cuts are tiny?

Not a lawyer.
I would have thought ABH, minimum.
Attempted GBH, possibly

But the CPS, which decides charges, has reasons that reason knows nothing of.

Blimey OP, are you and baby ok?
Police in attendance?

Is your baby ok? I hope so.

Yes, key word being "recklessly" in the circs you describe. Assault occasioning Actual Bodily Harm (ABH) – s47 OAPA 1861
The offence is committed when a person intentionally or recklessly assaults another, thereby causing Actual Bodily Harm (ABH). Bodily harm has its ordinary meaning and includes any hurt calculated to interfere with the health or comfort of the victim: such hurt need not be permanent, but must be more than transient and trifling. It is an either way offence, which carries a maximum penalty on indictment of five years’ imprisonment and/or a fine.