From Andy Rix's article here on Soul Source
" Despite the fact that the ‘Eddie Foster’ bootleg had sold thousands of copies, UK Tamla Motown decided to issue the record.
The original tapes for both sides of Soul 35019 were requested to be sent to London from America. However, when the tapes were received, they were stereo masters and not the original mono masters. UK Tamla Motown label manager, Gordon Frewin, instantly spotted the technical differences and corrected them at Abbey Road Studios, with the help of his engineer Chris Blair, and the benefit of a copy of the ‘Eddie Foster’ 45 taken to the studio by Motown collector John Lester. TMG 1170 was thus taken from stereo masters but folded into mono for its eventual release on 9th November 1979. "