Hmmmm well not quiet sure what the good Captain is referring to with Key To The Highway ( Full version by Ian Stewart) but with Let It Rock I take it he means the official release which is from Leeds March 13 1971 and is available on:
7"EP B-side of Brown Sugar - UK release
7"single Let It Rock/Blow With Ry Germany
LP Sticky Fingers stereo - Spanish Release
ROCKMAN