I think I might have figured it out, have been going through the game removing things and trying to see if something like a texture was breaking the game and it turns out that it has been crashing because of a lighting error.
It is an error with overlapping light and I completely forgot about it and didn’t fix it, fixing that issue now has got the game working again when package for Development, just need to test Shipping now.
Strange that the lighting error only crashes the game when it is packaged and not when it just launches from UE4.
Hoping that this is all ok, will confirm once I have tested the shipping version.
Thanks for you help though!
Tom