Actually it isn't a matter of English and Metric, it is proportional and actual. 1/32 can be metric as well. 1 can be an inch, a cm, or a mile. As long as both numbers are the same units it is true. 1 cm =32 cm and 1 inch =32 inches What you are calling metric is actually a common practice for figures only. 54mm means the figure is 54mm tall or would be if he were 6 ft in this scale.
Here's one for the smaller scales.
http://pages.zdnet.com/sfclarke/vietnam/id17.html