I honestly, am not sure how to go about a repo in this case. The background texture is 10 x 320 for 480 x 320 and 20 x 640 for 960 x 640 screens (multi res atlas). which shouldn't be to many polys (32 x 4 =128 triangles) That might be too small a texture and too many polys, but I'm not doing any optimization at the moment.
Initially I didn't have a problem, but as I was working on the project adding other things to the project, it just got a to a point where it wasn't happy with the background and was barking memory errors. I have since then removed the background and started a duplicate of the project which seems to ok, for the minute.
I can send you the files privately if you want to have a further look.