Mills and Boon Special Edition
The Silhouette Special Edition titles were introduced in the United Kingdom in January 1982 by Hodder & Stoughton, six month after the start of the North American Edition. At that time Silhouette still was a division of Simon & Schuster. The UK titles had the same covers and numbering as the US Edition but their publisher's ISBN: UK-Edition and US-Edition
Harlequin Enterprises Limited bought Silhouette in 1984 and from January 1985 on the UK-Edition was published by Harlequin's UK-based branch Mills & Boon. The UK titles still had the same covers and numbering as the US Edition but a Harlequin ISBN Prefix, whereas the US-edition still had the one of Simon & Schuster: UK-Edition and US-Edition
From July 1985 to June 1986 the UK titles were almost identical to the North American Edition. From July 1986 to April 1995 they had again a different ISBN with the Harlequin ISBN Prefix, but kept the covers and series numbering.
This changed in November 1993, when with a double #823 Mills & Boon discontinued to issue the American Edition on a 1:1 basis. Titles from the Harlequin American Romance and Silhouette Intimate Moments imprints were included and the series now had a special Mills & Boon numbering. The books kept their ISBN from the North American release, which makes it rather difficult to distinguish between the editions.