Trade ? Like Partco ?
I use two Partcos. One's near my place (Bristol), one's up at my parent's place (Southport), where I also have much more covered garage space and thus tends to be used for major car fettling. Bristol is still a sensible factor that sells wheelbearings, but the Southport shop is turning into fuzzy-dice and blue underlights for the noisy Nova crowd. As car reliability improves, the "old" model of a trade factor is changing. The other factors I use either don't even sell oil, or just sell their one favoured Valvoline brand and aren't cheap about it.
Halfords is cheap for high-quality own-brand oils.