For Social Policy essays you can pretty much choose any legislation the government has introduced and explain the way it has affected families.
For Example (basic plan, obviously say more);
Legislation: In 2015, Shared Maternity Leave came into place.
Affect on family: Women no longer has to be the only one caring for child, the maternity leave can be distributed between the mother and the father.
Link to ideology (if you can): Feminists would commend this as it means the women no longer has to sacrifice her career/opportunities to care for child, responsibility is shared, also add a sociologist if you can.
Basic plan, I would do about 4 different policies, maybe one on gender, class, ethnicity and education but always link to the family. If you want a a higher grade always do 1 policy from a different country, for example, China's 1 child policy. Remember to always link to how it has affected the family, such as changing the structure, responsibility, income, support etc.
For Unit 1 I have a feeling Social Policy or Childhood may come up for the essays.
Hope this helps