Thank you for that clarification, Mamba. I do not believe that Grimmer, Grimmest modifies any item stats - as you said, only increasing monster spawns and stats.
I think I will install a second iteration of GD Stash as I want to keep the items collected from my Vanilla characters separate to that which my mod characters collect.
Can you advise what I need to do to tell the 2nd instance of GD Stash to allocate the items collected from the modded character to a database that does not contain the items collected from my Vanilla characters? A completely separate database, as such.
Perhaps a step by step guide if you are feeling extra generous, Mamba