Ironically, 'parts' of these WERE heard in the north-east of England in 1975.
I had bought the first Metro Radio PAMS package in 1974 and (in my capacity as 'jingle freak) had been able to 'milk' demos out of Tanner! I spliced some of the intros on these onto parts of the PAMS package…. I doubt if anyone in Memphis would have been able to hear this !? 
I believe, these featured the Dallas singers (maybe Jackie Dickson on lead?) and did Chris Kershaw maybe write some or all of them? The box was labelled 'Thunder Productions' and there were several other packages in this style at this time.
Len