Super-Villain Team-Up #5, published c.January/February 1981, $0.60
Black Panther #7 published c.August/September 1981, $0.70
There is an interesting relationship between these two issues which I'll try to unpack with a bit of legwork and guesswork, and then sit back and see if I end up with egg on my face.
Yaffa issues carried three stories per issue (cropping and editing notwithstanding). Super-Villain Team-Up #5 reprints the main features from Super-Villain Team-Up #'s 13, 14 and 15 (the source for the cover of #5). Only two more U.S issues of Super-Villain Team-Up were published, which is not enough to fill a Yaffa issue, and as far as I know, Super-Villain Team-Up #5 was the last issue in the ongoing Yaffa series. This leaves two Super-Villain Team-Up stories unaccounted for: Shall I Call Thee Master? and Dark Victory.
As far as I know Black Panther #7 is the last issue in the ongoing series. Black Panther #7 reprints The Beasts in the Jungle! and Revenge of the Black Panther! from the last two issues of the short-lived Black Panther (1977-1979) series. Again, not enough material to satisfy a complete Yaffa issue. But, in this case, the extra pages are filled by the 'missing' U.S Super-Villain Team-Up #17 story Dark Victory.
The Black Panther story continued in Marvel Premiere #51. It's possible that Yaffa reprinted it, but given the filler backup in Black Panther #7, I doubt it was in a Black Panther #8.
This still leaves Shall I Call Thee Master? out in the cold. I'm assuming it was reprinted, but I don't know where.
It's possible there is a Super-Villain Team-Up #6 comprised of Shall I Call Thee Master?, Dark Victory and another backup story, but I strongly doubt it. The next instance of a Yaffa Super-Villain Team-Up issue that I'm aware of is this unnumbered $0.75 digest-sized reprint of #1:
I suppose I should confirm that Super-Villain Team-Up #5 and #NN are both 'short' digests and Black Panther #7 is a 'long' digest, but given the dates and cover prices and # information above, I figure we're all au fait with that now.
Anyway, it's now a matter of sitting back and seeing if and where Shall I Call Thee Master? turns up, and whether there are such things as Yaffa editions of Super-Villain Team-Up #6 and Black Panther #8.