After a bit of thought and discussion with those in the know (i.e. someone who has rebuilt a rotary engine before) it turns out that the engine that I declined initially could be fixed and relatively cheaply.
One of the benefits other than a cheaper price is that when the engine is rebuilt is will be better than an old second hand one and will also be tweaked a bit to make a bit more power, cant leave it stock when I rebuild it can I??? hehe
I secured a very very good price and made payment today. Another bonus is any of the damaged parts such as the charcoal canister and cold start air pump will be replaced for free once they get another RX8 in. Given that I want the clubman going in about twelve months that gives them ample time.
I also bought an electronic RX8 workshop manual today which should have electrical diagrams in it. The wiring is probably the trickiest part of the build, but it will be the second time I've rewired a car/engine. So while I am waiting for the chassis to arrive I can spend the next month or so going over the wiring harness and trimming it down to just the bare essentials (no air con, heater, power windows, door sensors etc etc etc).
Not long now until I start clogging up my friends garage with clubman parts, very exciting (for me that is!).