[Overdriven]

Looking at the pics I can see the upper arm is pointing up while the lower is horizontal. Now look at the arms like a compass and draw an arc at the ends. As the suspension compresses the upper arm essentially gets shorter faster than the lower, creating the rising camber. Since camber is the knuckle moving in and out from the truck, it always effects toe. Making sure the tie rod is as close to parallel to the lower arm will help, but raising the upper arm mount is the best fix.

Whether or not the issue is bad enough to be bothered is up to you. I don't know much about MGT's but I kinda figured you couldn't get away with just shimming the mounts, that would be too easy! Maybe flipping the mounts over? Just throwing out ideas.