Information from Finlay Forbes (by email):  
*"Bonnie Charlie" appears as "Bonny Charlie" on Page 5 of the third part of Gow's Repository, in which it is described as "A Scotish (sic) Measure" with instruction to be played "Slowish".  In its day, it probably sounded a bit like a "Lea Rig"/"Duchess Tree" style of strathspey.*
