About MP, my fiancee emailed our local MP and we send that as a part of evidence were my fiancee emphasize the discrimination over our friends case. The MP did write to Theresa May of Home Office but until now we don't get an answer from her.
About sending emails, I think at some point they noticed how disgusted we are with their service. To be honest, I don't think they will take that against us coz we are tormented by the wrong decisions of the ECO's. I always ensure that i tell them, "please try to understand the situation... hope that the ECO will be sensitive enough to genuine relationship" (something like that) even if my letter seems "rude"