I've just rung Pluto Press, who tell me that the paperback and hardback editions are out now and can be ordered from their website at http://www.plutobooks.com/shtml/aboutpluto.shtml

Bibliographical/pricing info listed on the site is;

CLASS ACT. Ben Harker

Paperback. 9780745321653. £15.99. $24.95. €23.00
Hardback. 9780745321660. £55.00. $75.00. €80.00

I mentioned the fact that it is shown as not yet available on Amazon, and am told that delays of this kind are fairly normal normal with them.