Very difficult to resolve this one I think. So much of the information could be suspect.
There is definitely no birth registration for him under Askey. Which as lyn mentioned could mean he was not registered.
Alternatively he could have been registered under another name, if for example he was illegitmate. He then may have taken his father's name (if he knew it) or his step father's if his mother re-married. However that doesn't help much because he doesn't appear on a census before 1891. I've looked at a number of George Alfreds registered Bham & Aston but none of them see likely.
If he was illegitimate the father's name and occupation could be suspect, possibly made up or a combination of a real and step father. It's also complicated by the name on the marriage and censuses. Was it George Alfred John or a different order maybe.
The complete absence of any likely Frederick Askey makes everything tricky. George naming a son John Frederick does seem to suggest someone named Frederick (father, step father, grandfather) but in a time before everyone could read and write his name could have been something else - Askew, Haskey being the most obvious.