Ford Fiesta Mk6 Dashboard Dials & Light Issues

I was recently given a 2007 Mk6 1.4 TDCI Fiesta in exchange for a failed engine replacement in  my 2008 Focus. I had the car on a weeks trial and it's an amazing little car. When he gave it to me first, there was an ABS light and a Drive Train light that would come on at times intermittently. The mechanic explained that he would repair this if I was taking the car.

I agreed to take the car and he took it in to do the work. When I got the car back, I noticed 1/4 of my diesel was gone. Obviously I thought they were spinning round in it. It wasnt until I noticed that the drive train light wasnt coming on in the first ignition position that I suspected something wasn't right.

I then noticed that all of the dials on the dash were reading lower than they should including the speedometer which showed me doing 50kph when the roadside speed signs registered me going upwards of 60kph. Even the temperature gauge rarely goes above the first position when it should be in the mid point when up to temperature.

I'm loath to bring the cr back to the same garage as I've done some digging since and heard horror stories. 

The car itself is a great little car and only has 133,600 on the clock. It's immaculate inside and out, drives great and is a miser on diesel.

Is there a way to get the dash lights tested to see if any have been disabled and can the instrumentation on the dash be reset? 

I've had terrible luck with my last few cars and spent a small fortune on repairs so something cheap and easy would be great. 

I cant guarantee I'll be able to keep my cool if I have to go back to the previous guy again.

Any help or advice will be gratefully received.