Christina and I have most of the progression of printings of this issue from 1986 to 1987, and the copyright pages bear out what I understand of Allen & Unwin's practice at the time.
The first of these, when the 'fourth edition' of 1981 (a reprint of the reset 'third edition' of 1979) was reissued in the 'Unicorn' series with new cover art by Roger Garland and an added cover device, is indicated on the copyright page as 'Re-issued in Unicorn 1986', with nothing further (thus the first printing in this sequence).
The next printing has: 'Re-issued in Unicorn 1986 | Reprinted 1986' (thus the second printing in this sequence).
The next has: 'Re-issued in Unicorn 1986 | Reprinted 1986 (twice)' (thus the third printing in this sequence).
We don't have a copy with 'Reprinted 1986 (three times)', but we do have the next (the fifth in the sequence -- always assuming that the publisher got the numbering correct, and didn't skip any), which has 'Re-issued 1986 | Reprinted 1986 (three times), 1987'. By this time, the 'Unicorn' cover device was gone, the series apparently having been discontinued as a marketing effort, which would explain why it has 'Re-issued 1986' and not 'Re-issued in Unicorn 1986'.
Unless something has changed since I did bibliographic work there, e.g. records having been found and transferred from HarperCollins, the Allen & Unwin archive at Reading can't come into it for books of this date: the records end long before 1987.
Wayne
The first of these, when the 'fourth edition' of 1981 (a reprint of the reset 'third edition' of 1979) was reissued in the 'Unicorn' series with new cover art by Roger Garland and an added cover device, is indicated on the copyright page as 'Re-issued in Unicorn 1986', with nothing further (thus the first printing in this sequence).
The next printing has: 'Re-issued in Unicorn 1986 | Reprinted 1986' (thus the second printing in this sequence).
The next has: 'Re-issued in Unicorn 1986 | Reprinted 1986 (twice)' (thus the third printing in this sequence).
We don't have a copy with 'Reprinted 1986 (three times)', but we do have the next (the fifth in the sequence -- always assuming that the publisher got the numbering correct, and didn't skip any), which has 'Re-issued 1986 | Reprinted 1986 (three times), 1987'. By this time, the 'Unicorn' cover device was gone, the series apparently having been discontinued as a marketing effort, which would explain why it has 'Re-issued 1986' and not 'Re-issued in Unicorn 1986'.
Unless something has changed since I did bibliographic work there, e.g. records having been found and transferred from HarperCollins, the Allen & Unwin archive at Reading can't come into it for books of this date: the records end long before 1987.
Wayne