Looking at the aerial photo on google maps, the one in Unstone is just down the road from the Fleur de Lys pub on the B6057, behind the old petrol station.
I'm pretty certain this is where I remember going as a kid, as I remember waiting for a bus outside, and a railway bridge, both of which are right outside the breakers yard. If you are right, and it was never Universal Salvage, then I have another theory. I remember Dad being made redundant, so if this coincides with the time that U.S. stopped breaking cars, then I guess that was the reason why he lost his job, as he was a welder. Maybe where I remember going wasn't U.S. at all and some other breaker he started working for.
Any idea of the year Lockoford Lane was re-routed?