Hi. My name is*****'m looking at your question now and will post my answer or ask for more information here in a short while.
Is this a bond whereby withdrawals could be made of 5% of the original capital per policy year? Were any such withdrawals made? Who are the named beneficiaries of the bond (not necessarily the same as the beneficiaries of the estate)? What does the bond say about what should happen to the cash on the death of the life assured, your father?
I shall have to opt out of this as I'm not familiar with trust set up arrangement you have or the circumstances as to why the life office won't pay the loan back to the esate.