When is irony used in the short story, "The Rocking Horse Winner"?

There are two main forms of irony employed in this
excellent short story by D. H. Lawrence. The first is situational irony, and we are
presented with an example in the very first paragraph. Here the author introduces us to
the mother in the story who is undergoing a conflict between appearance and
reality:

She
had bonny children yet she felt they had been thrust upon her, and she could not love
them. They looked at her coldly, as if they were finding fault with her. And hurriedly
she felt she must cover up some fault in herself. Yet what it was that she must cover up
she never knew. Nevertheless, when her children were present, she always felt the centre
of her heart go hard.

The
woman appears to love her children, and in fact we are told that everyone else says of
her she is a very good mother because she "adores" her children, but in fact, her heart
was "a hard little place" that was incapable of loving
anyone.

The second type of irony we find is dramatic irony.
We, Paul and Uncle Oscar know the source of the money that Paul's mother receives, but
she does not. It is clearly ironic that what is a gift of love and a result of care and
concern for the mother is responded to with such avaricious greed and rapaciousness.
For, we are told that after receiving the first instalment of the money, Paul's mother
went that very day to the lawyer to ask for the whole money at once. It is likewise
ironic that Paul's mother doesn't realise what Paul is doing to himself until it is too
late.