Yes It was definately Rob, He had the Kell Osbourne Inst C/U as Harlem Tremble.
I played Dave Charles 1st at 100 Club in 1987/88
Ady played Juan Williams C/U as Richard Temple "A Letter From You"
Yes mate, the last two Four Sonics releases were pressed by Amy-Mala-Bell, this is probably when duplication ocurred, though "It Takes Two" also came out on the yellow Sport label with matrix numbers just before the Appreciations release.
Plus this number is a duplicate, just as Sport signed a distribution deal with Amy-Mala-Bell, which didn't seem to be much of an advantage to them as they folded soon after!
I've got a white demo, not to hand though, doesn't it have 'AT' in the run-out? I also had a copy like the one you have Bob, with the repeated title on the flip, I sold it it as a boot a few years back.
Dave Thorley played it at TOTW a few times too, I got a copy at that time from Ady Pountain for £3, personally I don't rate it as a 3 figure sound, but, heh who's to say?