Being the day the book is out, I took a peek in a couple of bookshops in town, and saw one small pile lurking in the corner of one of the Waterstones. It's a start, I guess. The cheapest I've seen it online is just over a tenner, at www.bookdepository.co.uk, a site I've already used myself for several purchases (that's postage free, by the way, here in the UK).
Another good review, this time at Fantasy Book Critic:
"In conclusion, I’m extremely grateful to Pan MacMillan for sending me a copy of “Stealing Light”. Otherwise, I might never have been introduced to Gary Gibson who is definitely an author to keep an eye on. And, I might never have read “Stealing Light” which is easily one of the most enjoyable science fiction books that I’ve finished this year, and would make a great starting point for readers new to the genre…"