Hi Scan - I don't know much about the social welfare entitlements. Hopefully other posters will answer your questions.
However, I'm wondering how realistic the scenario of the mother rearing to the family to age 65 is? Surely many mothers will have their rearing done much earlier. For example, my mother in law has returned to work now in her fifties and is earning her stamps.
Also, isn't there an obligation on the family to meet this requirement? Even in cases of seperation or divorce, the pension entitlements of the breadwinner are usually divided between both parties.