So you need to open up the gap for the helmet lock to work. I recommend a large flat bladed screwdriver and a towel. Use the towel to protect the paint work
Just a gentle push is all it needs to move the metal a few millimeters. This will allow your D ring to pass unhindered, and allow you to still lock the seat in place.
And that is it, this is an easy mod. You don't even need to do this if you don't use the helmet lock.