Sweet frame Wookie!
A 19" one owner frame with original decals with a VGC 2006 Rockshox SID fork sold on ebay last month for GBP450. Cannot confirm the year but i think should be a '97 going by the original yellow decals and semi-shiny brushed finish.
Another 19" two owner frame failed to sell on ebay 9 months ago for buy-it-now GBP450 or GBP500 (can't remember which). It sold later through Retrobike at GBP400. It's a '99 matt shot-peened finish with decals and red headtube paint removed.
Those two frames were definately not stolen.
The 19" currently on ebay i know nothing about, but according to the seller a '99 with '97 repro decals. I'd say the buy-it-now GBP700 is adventurous, the above prices are actual transaction prices within the last 12 months.
Not sure if your early year adds value or not? I guess it's rarer but does it have pre 'suspension corrected' geometry? That might detract for some buyers..? Are you sure about selling though? It's a classic, you've had it since new and you're obviously still into retro MTBs... Once gone the regret might creep up on you!