Left Wing Mirror not adjusting

[Quin452]

Hi guys

My mechanic says that I need a new door control to operate my left wing mirror as there is no power going to it. The right works fine, moves and makes a slight noise (the mechanics at work), but the left does nothing; when I bought the car it "was working before" - typical.

Is it the control? How much is the part to replace (luckily I've been told I won't fail the MOT on it) :-D