In reply to BigHairyIan:
If its a TNF Snow Leopard from 1994. Im sitting here with the specs in front of me like a sad git on a Bank Holiday!
As you look at the back of the rucsac, to the outside of the riser straps (which connect the rucsac strap adjuster to the main body of the sac) there are two other buckles. These should be connected to tapes to adjust or remove the detachable top pocket (which is also held in place by a velcro tape in the middle)
Possible to just about see it here (although the central velcro tape is not fastened)
http://smg.photobucket.com/user/Mogas/media/Bacpack3.jpg.html
http://smg.photobucket.com/user/Mogas/media/Backpack2.jpg.html
Off now to collect train no's ....................
Post edited at 15:36