All of those will be able to do a good job, I’m guessing the price difference is the labour charge which does vary across the country. McGraths are now servicing the more modern cars and provide a great service. They will also tell you anything else that requires doing as guidance notes. So you can choose whether to have them done.
I’m going to visit them in a few weeks for the open day so if they are near you pop along and have a look at their facilities.
Have you thought about calling them and see if the others price match or lower the price. Otherwise, they are all good options to use.