Thanks for the suggestion Gerard. Whilst this does allow me to relocate the grid, I need this to be more automatic. I am constantly exchanging between files and to do this manually each time would be a massive pain to do.
I would suggest that an additional setting allowing you to link the grids to a file containing the relevant GCS's should suffice. Or to be able to attach the GCS systems and transforms within the modify Grid models. This cannot be done at present as the grid models are just temporary.