wouldn't they have been transferred to the Court when probate was moved from Ecclesiastical to Civil authority ? - otherwise they would have remained in the Diocesan Archive held in the Vicar General's office (not that it would have fitted in the small filing system I saw when I visited Hills Street - since when I think Wendy has gained possession of most of the older material) - was there any formal legal arrangement re the filming in 1947 - I suspect not.
I know that when I inquired as an academic, about buying some films many years ago I was told that I needed the permission of the Manx Museum and that I coyuld speed up the process by attaching a permission letter from the Museum to the LDS with my request - in the end I just decided to spend long on the Island !