How come the question says the total liabilities for the company are £250m, but the sum of reserves comes to £424.5m ?
You don't take the unit reserves into account here because on a unit linked policy, the unit fund (ie the unit reserve) belongs to the policyholder as they take on all of the investment risk. I am thinking the total liabilities should be the sum of the Annuity and Term assurance reserves + positive value of the non-unit reserves.