Actually, according to their website, the vehicles are capable of having anywhere from -2" = 44" of clearance. From what I could see, it uses a Warthog-like suspension system (Halo), based on air-springs. The 44" of travel is for less than 10mph and the -2" is for allowing tire changes and stacking of vehicles for shipment.
All in all, it looks cool, but like most concepts, I seriously doubt it will ever see the light of day.
And speaking of the guys of Top Gear; It reminds me visually of their electric car they built, minus the center seat roof window, of course.:lol