MSA is decided by Rule 29 (i.e. 1000' above the highest obstacle within 5 nm). You are exempted from it if you are below 3000' clear of cloud and in sight of the surface or following an approach procedure.
I think that its more a question of good airmanship to adopt it as a x-country minimum. I can't recall if the JARs specify a minimum cross-country, but your training facility will probably ecpect something sensible for that part of the training.