Ok so I have found something interesting, looks like 5.0 had a nice feature slipped in for instancing blueprints.
Have a look at the following YouTube video to see how it works.
This could be exactly what I am hoping for, in the cases where I have 1,000’s of tiles that are blueprint actors I could use this, and all individual unique blueprint actors could just be added as normal.
This could be a game changer for me!
Hope it might help everyone else on this thread as well.