Old Fella, are you sure you're not referring to CX's
GE-powered classics? Those indeed did not have retracting LE flaps, but CX's RR classics did (or at least the four RR freighters we had at the end did). Here's the excerpt from my Vol 4:
(RB211)
When thrust reverse is selected after landing all leading edge flaps retract to prevent damage.
With one and four engines in reverse group “A” leading edge flaps retract. With two and three engines in reverse group “B” leading edge flaps retract. The retraction of the leading edge flaps is actuated as the thrust reverse levers move through 25° from the reverse idle position.