Right, here we are. My collection's a bit old school, so my apologies if the comparison figures aren't as informative as I'd like. To the left of Deadnettle the gnome is a Grenadier halfling, and to the right a pair of old Ral Partha dwarves.
The figure of 26-28mm includes their tall gnomish caps; Deadnettle is one of the taller gnomes and he measures 18.5mm precisely from the soles of his boots to his eye level.