FYI - Oil coller adapter ring
In order for me to upgrade my oil lines, I need an oil line adapter ring with the smaller 18mm orifaces for the lines as mine had the larger, although the radiator was correct.
Should someone else run into this issue, the LR part number is ERC 8501. The big O-ring for the adapter where it mates to the engine block is ERR852. I was forced to purchase them new from Rover's North as I was unable to locate one used. The adapter was $161.94 and the O-ring was $3.84.
These are now installed, leak free, and thus verified to be the correct parts. Just thought I would throw this on the board in case someone searches for it later. BTW, ty Mike for the help in locating these parts.