Cubic lines in Normal bake

Hi - I am baking a hi-poly model to lo-poly and I am getting these square edged lines on the UV seams as well as a diffence in the normal colors where the uvs meet.

I have tried various settings as well as playing around with the smoothing options on the models before exporting from Blender but no luck - any idea of a fix here?  I suspect it may be because I have had to scale some of the UV's to focus on some important elements of the model to make best use of the texture spcae - I cant get around that and it is where the two scales meet but this does not seem to be a problem on any of the other texture sets layers when baking.

Any ideas of a fix/workaround to this?

Thanks