Thanks for the replies and help guys, will try out the advice.
Think I put approximately the same pressures in SID as I used in my Fox just so it hold up the back of the bike.
I did have a look at Edinburgh Bikes website the other day but there's zilch. Might give them a phone but I don't hold out much hope as I have twice been there to get parts for my Lefty and Headshok forks and each time I've been taken through to one of the mechanics so he could have a rummage in his personal spares stash. This from a Cannondale dealer FFS. They no longer inspire me with confidence, years ago I wouldn't have gone elsewhere for bike stuff but no longer.
We were out on our bikes this evening and at least the shock is working well enough for my wife with the pressures I put in.
Obviously I'd rather have it set up correctly and that's where Rob comes in, thanks for offer of time-limited loan of manual.
Rob, I'll PM you where I live just to make sure, think you know already.