Hello Lyndon,
What you have there is the second evolution of the red model greenfield. Mark 1 had a seven slot grill, two piece rear body work and a dog clutch located on the deck and was only made for about a year, Mark 2 had the sixteen slot grill (to combat fuel boiling issues) and had the single piece rear body work incorporating the taper towards the steering wheel support panel, Mark 3 had a mesh grill and featured a G65 Honda engine, greenfield changed color to yellow soon after. your greenfield looks to be in great condition, just ripe for restoration. I think you greenfield would have been made in 1967-1969 but one of the local greenfield gurus will have to correct me on that.
Cheers
Greenfielder
P.s. I love the G60 and do I spy a forward-control land rover 101 in the background? (I have contracted the land rover disease)