I bought mine from e-bay, £6-8 per volume, the digital archive does not go back that far.
Are you thinking of building one, I have most of the castings stashed under the bench. Do be aware that its a Superba from a distance, up close Haining took quite a few liberties and some research will yield a far better scale representation. For example he shows 4No rivits per strake when there should actually be 14No, the front axle as drawn won't have any articulation, etc
J