Consider the age of the gearbox, other versions used different pads as they are called, very unlikely anyone will make these, not enough market to make tooling/sales cost effective.
Any ford dealer in the country can order them, what they can't get is delivery of the item!!
You can make a pad out of delrin etc if you really want to, or go concentric hydraulic, not with the cheapy/nasty slave cylinder burtons use but a fully metal one, from the usa about £160 all in but STEEL.
tabetha