There seems to be some agreement on the 1,2,3 hole thicknesses
ERR5261=1.3mm=1 Hole, ERR5262=1.4mm=2 Hole, ERR5263=1.5mm=3 Hole
It does get confusing when you get to the quoted thicknesses and part nos for the zero/4 hole gasket.
Paddock are calling ERR1754 a "No-Hole" (1.6mm Britpart, 1.69mm...