Possible Clues:

• There's not a foot in this system to meet 'er, by the sound of it
• Meet 'er in such a scaly way
• Came across Richard, but not by foot this way
• Like milligrams and milliliters
• Came across the old constabulary with no feet in the sysem
• Satisfied with most of a heap of verses?
• Came across the old force but not by foot this way
• Ton type
• Successor to imperial (system)
• Like a tonne of bricks?