Like Batman, Superboy and Superman, these were distributed in the UK by Atlas Publishing and were black and white reprints of the original US material though occasionally with new covers. Early issues are tough to find, especially in high grade.
In fact the first 20 issues were only available in Australia and not imported/reprinted over here in the UK. Issue #21 in early 1952 was the first Super Adventure to be published in the UK with a 6d cover price. Late issues often turn up in high grade with very glossy covers.
Note: some PR issues may have no value. Selected issues in FN, VF or VF/NM may not exist in some titles.