I've never seen an image of one marked like that.
Concerns I have with the authenticity:
-No serial on it(Not that it didn't happen on occasion, but mostly they were there)
-The fuselage roundel is like a PR Spit not a fighter Spit. The tail marking would have been smaller as well
My first thought would be someone had some time to kill and did a Spit Vc trop (with the wrong windscreen I might add) and did what they thought were Malta colors or PR colors and used decals they had in their spares box)
That being said, I'll keep looking to see if anything like that shows up anywhere in my stuff.
And as Kev points out, the SAAF used orange in their markings not red.