From what I can tell Chris, it looks to have arrived in NZ sometime in 1975. It raced at the NZIGP at Puke in early '76, and I've found details of it at other events during the 1975/76 season. Will go through and see if I can get you more details.

I did manage to find a scratchy picture of Warren Steel in a MkI ShellSport Escort in the early 80s in a Motoring News mag, but its a newsprint mag, so very hard to make out any detail, but the car he was driving is rhd. Do you know when your car was converted?