Hello All,
New to this so please be patient.
Have recently found out a distant relation to my father passed away last year in the Isle of Man

, have contacted the attorney general at the Isle of Man and have informed me she passed away with no will and no known relations, no children etc. There is a estate which might be substantial, she owned a house which used to be a guest house was big, last visited about 14 years ago.
We need establish a relationship between this lady and my father, we know:
She was my grandmothers half sister but do not know if by blood or marriage.
we know the area which they lived until they moved to the Isle of Man
The name of her husband and of course the relations to my father.
Can anyone suggest the best way to go about to gather evidence of how this lady is related to my father?
Thanks in advance.