John Grubb
From OSM Wiki for highway=track:-

"This tag represents roads for MOSTLY agricultural use, forest tracks etc.; USUALLY UNPAVED (unsealed) but may apply to paved tracks as well, that are suitable for two-track vehicles, such as tractors or jeeps." [Capitalised emphasis mine]

As it is an unsealed track suitable for jeeps (which is what the army use it for) with a gravel surface and it is not permitted to be used by public vehicles but can be used by people on foot or horseback (outside of live firing times) it would appear that it is tagged correctly. That the word "road" appears in the name that the Royal Engineers gave the track when they built it is immaterial.

As the range tracks are only suitable for 4x4 vehicles and are not public roads, nor are the public permitted to drive on them, they would appear to be unsuited to highway=unclassifed.
