Of course it has a chassis number. That the builder of the contraption may have removed it is neither here nor there, but it has a VIN allocated to it and taking an angle grinder to it doesn't suddenly make that void.
The test in court is whether the vehicle remains 'substantially intact'. It maintains its full silhouette as a Vauxhall Corsa C, and sufficient structure to maintain the cars extrenal shape and support every single external panel, so you'd have a hard time arguing to a court that it does not remain substantially intact. As aforementioned, I've run a successful prosecution for half a bodyshell turned into a trailer, so an entire complete bodyshell and monocoque will be a shoo-in.