I think its probably time to move on old faithful. I am sure you are aware this is considered somewhat of a benchmark in AM bikes and is still very desirable now.
The frame is in really good condition and still rides really well. The Monarch Plus is a real upgrade from the original DHX Air. It does everything well thanks to the three position compression damping (open, medium, firm), there is no lockout which I think on a bike like this is a good thing. There is no paint to be scuffed up so it looks really tidy, although a couple of the decals have got sliced or pulled off a bit through use but these arn't immediately obvious. All the bearings seem fine and cycle through their range smoothly and without issue. The only problem with the frame is that the shock stanchion is scratched, this could probably be smoothed over by somebody using the nail varnish technique. Having said that the shock still works really well because the damping is unaffected and it doesn't seem to lose any air pressure. Thats not to say it doen't, I just havn't noticed it.
My main reason for sale is that it is just too short for me. It gives me a bad back after only 30 mins of riding. I could do without this and I don't get it with my BFe which is longer so I can only put it down to the length.
I have a PDF of the owners manual that has all the geometry on it should you require it.
Its a medium frame and puts out about 155mm of travel thanks to having a slightly longer than standard stroke on the shock. I am 6ft but have a long torso so it will work for riders up to around 6ft if you have a normal length torso or are more flexible than me.
I am after £200 ONO for this plus £20 postage if it needs posting.
More pics here.