Main dealers do have special offers occasionally but in general they tend to be the most expensive in my experience. I use a local independent BMW specialist and his rate is <£100 per hour. I've used him for servicing and a couple of small repair jobs and he's proved reliable and fair.
In contrast, the wife's Audi developed a fault with the rear parking sensors not working. Main dealer wanted £105 just to analyse. Local garage charged just £75 to "analyse" and fix a broken wire between the gearbox and the sensor control unit.
If you've had a bad experience with an Independent, do as Dave suggests and look at the register to find another one local to you.