Publisher:Mayflower-Dell

1960s imprint of Mayflower

Addresses:

• 1963: "Mayflower-Dell Paperbacks are published by Mayflower Books Ltd, 282 Vauxhall Bridge Road, London S.W.1"
• 1964 - Aug 1965: "Mayflower-Dell Paperbacks are published by Mayflower Books Ltd, 319 High Holborn, London W.C.1"
• Oct 1965 - 1966: "Mayflower-Dell Paperbacks are published by Mayflower Books Ltd, Kingsbourne House, 229-231 High Holborn, London W.C.1"

The Best of Sci-Fi Series

Mayflower-Dell ran a series of Anthologies that don't exactly match any US series:

• Three is "Great Science Fiction Stories" for various years.
• Four is "The 8th Annual of the Year's Best S-F" for 1962.
• Five is "The 5th Annual of the Year's Best S-F" for 1959.

One and Two are listed as being by Judith Merril but there's yet no telling which books they're based on: checking ahead to Number 12 suggests they eventually synchronised though.