Rare i go to Halfords or any motor factors now as ebay has always been lower cost. At the garage, the boy uses local factors as they can deliver within 2 hours every day and he gets a very good price for parts.
Mannol oil from Germany, but UK supplied is exceptional value and the technical data is made clear. For a supercharged Mercedes, it cost around 18 pounds for 5 litres but the change needs 6 litres so the supplier will send the 6 litres required . I bought some 4T Mannol oil for my new bikes and it is half the cost of some brands for the same spec oil.