Jimmy's ex-wife Ann's lover, the effortlessly superior Dr Howard Banks, returns to London for a few days to sort out a funding grant for the African Relief project and pops round to the house to pick up a few photos for Ann.

Howard sets out to charm Diana, bond with the kids and castrate Jimmy in the process so he drops hints about the wonderful changes the family can look forward to when he and Ann return from their relief mission.

It seems that his proposed changes will "free up", or in other words totally exclude both Jimmy and Diana so they're forced to join forces in an unlikely alliance to protect their new family.