my mates Ford galaxy had a oil quality sensor! the oil level could be perfect on the stick but if the oil was of a low quality it would bring up a warning light! took us a while to suss that one!
as it wasnt in the user hand book! three oil changes later inc filters and the damn light went off
as for halfords, have had no trouble with them doing oil changes on my Jeep where as the garage that service my works van! over filled it
I had to slam it into third and dump the clutch while I stood on the brakes in order to stall it before it imploded!