Multiple Atlas terrains / TGEA now crashing

We are currently working on mapping the world out for our game and we finished getting all of America / Canada and South-America in, but when we finish compiling the UK and started on getting the top part of Africa in TGEA now crashes. If I remove the UK I can place many more tiles in that are way more detailed then the UK tile is. Has anyone else had this problem and anyone know what a good fix is?

this is an image of the current terrain