ISBN anomaly

[Beorn]

This book appears to match all the credentials of the copy I've got only the ISBN is completely different.
http://www.goodreads.com/book/show/84...
It has the same page count, publishing details and cover...

[Cait]

Is there a record for the ISBN on your book?

[Beorn]

Yeah, sorry. I realised after I turned the laptop off that I should have included the ISBN-13 on my copy.
It's 9781407230092

There's a little side barcode next to the main barcode with a number above it of 00799.
There's 244 numbered pages but two extra pages with a biography and a list of other available titles in the 'SF Masterworks' series.

[Beorn]

Hmm. On the back cover Gollancz looks like the publisher, but mentions underneath 'An imprint of the Orion Publishing Group Ltd' with Orion Books website.

Some of the publishing info from the page inside:
First published in Great Britain in 1999 by Millennium
An imprint of Orion Books Ltd
...
This edition published in Great Britain in 2010 by Gollancz
An imprint of the Orion Publishing Group

So maybe the difference is one was published by an Orion Books imprint the other by an imprint of the umbrella Orion Publishing Group. If that makes sense.