Here's a few update photos, I'd really like to find out 100% which year this came from. It's still work in progress, nothing done beyond the stuff I mentioned in the last post. Saddle and post borrowed from my other Diamond back until ebay provides a replacment (other post was too short, even for me).
The following may help date the bike; 26.8mm seatpost, 1" headset, 68mm bb and AVR tubing.
I've had a look at my 91 brochure, now, and I'd go with this being a 90.
The 91 model, according to the brochure - and the picture of the frame tubing decal - didn't have AVR main tubes, but "100% CR-MO mountain tubing".
Colour was a solid grey, with bright pink forks ("Rich Grey - Neon Pink Duo") and mainly pink decals on the main tubes. Forks were curved but did taper (unlike all the models above it in the range).
Brochure doesn't list the BB shell width, although it does for all the bikes above it (ie Ascent upwards) - and they're all 73mm BB shells.
300LX groupset, Weinmann 2121 rims.
As I said, I think yours is a 90 model - which I'd see as a plus - the paintjob on yours is nicer, and according to the brochure spec, your frameset possibly higher spec'd than the 91 model.
edit: proper bargain, that