Estate debts and pension annuity query

[SoConfused]

My father had a pension savings plan with Scottush Widows which should have been used to buy an annuity when he reached the age of 70. He originally took this out to support a mortgage for a property which he later sold. however, he never actioned the purchase of an annuity with Scottish Widows at so the money he had paid in just sat with them until he died last November age 73. I am waiting to hear if beneficiaries were named for this, but am not clear about what should happen to the money if there remains debts for inheritance tax to pay on his estate.
I am being told that it falls outside of the estate for hmrc tax calculation purposes, but does that also mean the funds from it can be distributed before estate debts are settled? i dont want to do the wrong thing as his estate is otherwise property only, which is still to be sold so settlement of debts cannot proceed until a buyer is found for the house.
Any advice gratefully received, thankyou.