I had a bad experience with national tyres with my oil change, they left the car sitting for 4 hours before starting the oil change (even after phoning ahead an hour before i got there to see if they could do it), never warmed up the engine to drain the old oil, it took the guy 4 attempts to get the correct tool to remove the sump plug, then after he finished the oil change he started the car and revved the tits out of it and drove my car around the car park like an idiot,
He also put 7liters of oil into the car as I found out when I checked the oil level the next day and had to drop over 2 litres from the car myself (only used them to save the hassle of getting oil in the car park and having to transport the old oil to the skip)
This was the Aberdeen branch and I was assured by the management of national tyres that this was a rare case but I would be watching them like a hawk when doing the change
I like to Change the oil In a car every 5k or 6 months so will be using vw every year and my usual garage for the in between services and work that requires a ramp