Only £140? Even with some of the later kit, that's a decent price for the frame. Check for dents and cracks. I think it's a 20" based on that head-tube length and if it is, it's one of the few I've seen in that size.
https://www.gumtree.com/p/bicycles/kona ... 1197998851
It's not quite as old as the ad lists
https://www.gumtree.com/p/bicycles/kona ... 1197998851
It's not quite as old as the ad lists