Original US copies of DC Comics didn't start getting distributed in the UK until the early 1960s. No British publisher had reprint rights at the time, but all the same black and white reprints were readily available at newsagents around the country thanks to an Australian company who did have reprint rights and exploited a hole in the market. K.G. Murray published a number of licensed comics featuring DC's most popular characters in Australia, and for the UK market they printed seperate editions with different covers, price tags, adverts etc. Another noteable difference was the fact that the Australian versions had newsprint covers, while the UK editions had glossy ones. Most editions were in black and white, but for a short period around 1956/57 they were printed in full colour.
Super Adventure Comics
The first 21 issues didn't have seperate UK covers, it was only from issue 22 onward that they were seperate editions.