Thanks for the useful suggestion of ACT as a different type of therapy to try, Eilatan. I'd vaguely heard of it but didn't know what it really involved, so thanks for the explanation. Next time I see my pdoc I think I'll ask him about it to see if it's something my Trust offers. Good luck with the rest of your sessions. Like you said, it sounds hard work but hopefully it's something that will pay off in the end.
Oliveira, it's good to know you've managed to use some ACT style techniques already and that they've helped you out. It's particularly impressive you've managed to employ them to some extent when manic/paranoid!
Come to think of it, I seem to be able to distance myself from my thoughts a bit easier when (hypo)manic, as long as I'm not too far in to the mania/psychosis, than I do with the usual thoughts I have when stable. I think it's because I've been through so many highs, it's fairly easy to identify them as 'manic thoughts', whereas with the negative automatic thoughts I have when I'm otherwise well, I tend to accept them as true, and that's where they get distressing. Hopefully attempting to diffuse the thoughts rather than challenge them might prove more effective. Thanks again, guys!