Just a quick note. You will often have to advise a testator that they owe a moral duty to their children. So how does that work in mutual husband and wife will situation? If a husband leaves his entire estate to his wife, has he not failed in his moral duty to his children. Can they not make a claim?

The answer is no. The reason is not because the wife is presumed to look after the children and thus the moral obligation is satisfied. No. Its due to s. 117(3) of the Succession Act.

This effectively states that an application under s. 117 cannot alter the spouses legal right share or any bequest to a spouse. The share is ring fenced. So the pot available to any claiming child is what is left after that. So really s. 117 claims tend to be in cases where the last survivor of a marriage dies.