If you don't follow Dave Walkers running commentary, you might not know that Christian book chain SPCK has been taken over by the St. Stephen the Great Charitable Trust. If you want to know what they're about, have a look at http://www.youtube.com/SSTGCT and watch the video, or read Dave's blog.
It seems to be a splinter Orthodox church (not actually part of any of the main Orthodox patriarchates) who want to do up old church buildings, like a religious version of English Heritage. By all accounts their handling of the SPCK bookshops has been draconian, so you might want to be aware of exactly what you're supporting by buying through the SPCK chain. The publishing arm of SPCK remains independent, so fear not, Tom Wright isn't on board with this, even though he has the beard for it.