"Could someone suggest which of these papers has a surface most similiar to unglazed, air dried glossy fibre?"
Nigel, for the Claria dye ink printers, the Harman Gloss is very close. For K3 printers, Innova Semi Matte. However, the printed image on the Innova paper is glossier than the paper because of the gloss optimiser incorporated in the inks, which leads to dull-looking spots in specular highlights (not enough ink = not enough gloss optimiser). Also, light blue areas bronze dichroically (reflect red), which is an annoying bronzing problem with the light cyan ink, maybe cyan too.
The Innova Semi Matte/K3 combo works best for black and white prints, using Epson's Advanced B&W.