Here are some quick pictures I have all of the original parts except tires.
It looks nice without the yellow splatter. It seems to have a lot of the Deore II parts maybe the owner just upgraded some to XT over the years. It's also sounding like the uk versions were spec'd different to the ones for the American market if the 89 spec says XT parts because all i've seen in the catalogue is Deore II then the 1990 Explosif had suntour parts and also the rack mounts your talking about we're removed,well at least the ones on my 90 Explosif have. Why not contact kona see if they can throw light on why yours is a bit different.
Konas:1988/89 Fire Mountain,Cindercone,Explosif.
Kona: 1992 Lavadome,1993 Lavadome
Muddy Fox: 1990 Pathfinder
1992ish Dave Yates Diablo
Denton Cycles: 1995
Saracen: 1989/90 Killiflyer