Neither of the following two SF covers from the mid 1970s includes a credit for the cover artist, neither artist signed his work in a spot that couldn’t easily be cropped out, and neither artist has been identified by other means by the folks at isfdb.org or any other reputable site, but based on appearances, I would say that the two covers are, at the very least, very likely by the same hand…
[CLICK IMAGES TO ENLARGE]
Shortly after I posted the above scans, a reader, Cyrille, delurked to say that the artist might be Peter Lloyd. And you know what? I think Cyrille is right!