As I have previously posted on the BLT2 I know you think I'm biased, but listening to your needs, why not try and have a look at the Cotic Hemlock. If you are a long term hard tailer then you will enjoy it more than either the SC or the O5. Singletrack raved about the hemlock. Trouble might be getting hold of a demo, but just call Cotic, they always seem happy to help. On other demos, I know you can get demo bikes from Pedal and spoke at peaslake in the Surrey hills. Not so sure where to go
For an orange demo in that area, but the Surrey hills really helped me to choose my current bike(blt2). I would get a mate to go with you, hire both bikes in the correct size for you( very important for blur, and also make sure shock pressure is in the zone for the blur, and then go and ride the same trails on the different bikes.
TBH it always surprised me when LBS's expect you to part with a large amount of wonga based upon faith alone...