Australian heavyweight Big John Marshall reported wrestling an Englishman with the name Guy Mitchell in 1969. Most of his matches were on the Sydney club circuit though we have heard of one high profile match on September 12h when he lost to Murphy the Magnificent (Maurice LaRue in the UK) at Sydney Stadium. Whether or not this was our man we cannot say. We have records of Guy Mitchell contests between 1964 and 1979.
Big John, who was Arthur Little, was probably thinking of John Hill, who toured Australia and even held the World Title Aussie version, as THE DESTROYER. For a few weeks, among those that were said to be ‘coming in soon’ was Guy Mitchell, then he was ‘coming in next week’. Next week arrived and no Guy Mitchell on the Sydney card, however an unheralded THE DESTROYER does appear and reeks havoc (despite being a pretty much mid-card guy (no pun intended) to me, weeks before being unmasked by Spiros Arion. Even at a young age I was savvy enough to believe the Destroyer was Guy Mitchell when the latter didn’t materialise. Guy / John had a good long career, using many aliases.
Alternatively, an Aussie club wrestler, may have pinched his name during that same period. If Kirk Beatty was still around he would be able to elucidate.
John Marshall wrestled in NZ a couple of times (will have a photo somewhere). Guy Mitchell also wrestled here.