I'l ike to know this too. My guess is that the cars were supplied with both a UK and possibly a German manual as well since the cars were produced at Koln. But Ford Dearborn probably supplied the UK manual for a translation.
I know over in Europe it isn't unusual for a manual to be in multiple languages for cost and efficiency concerns. Could this be the case with the Fiesta, wouldn't doubt it.
I'd be very interested to know if the UK english translation is exact to the german version or if they are significantly different in the information they each contain. Often times I've found from experience that german language manuals, technical publications, even car magazines often have much much more info content than their english counterparts.