The DT file is taken from a record by Frankie Armstrong; her source is not made clear, but the text looks to be a slight modification of that printed by Frank Purslow in The Wanton Seed (EFDS, 1968).  This was a collation of a partial text noted by H.E.D. Hammond from the prolific Mrs. Russell of Upwey, Dorset, in 1907, and a broadside text printed by Disley.  The tune given is a close relative of Mrs. Russell's, and without knowing the facts I'd guess that Frankie learned the song from Purslow's book and changed it during the course of performance.  A copy of the Disley sheet can be seen at  Bodleian Library Broadside Ballads:

The crafty maid's policy  Printed between 1860 and 1883 by H. Disley, 57, High Street, St. Giles [London].

There are two other versions of this song in the DT:

WHEN SHE GOT THERE  A Wisconsin set from Pearl Jacobs Borusky, 1940, with tune.
SWEET JOAN  From Stephen Sedley's book The Seeds of Love (Essex Music, 1967).

Frank Purslow, who was not entirely impressed with Sedley's scholarship, commented "Sedley has... unaccountably confused the song with one usually called Lovely Joan and the result is verses from the Crafty Maid's Policy broadside set to a Lovely Joan tune."

In fact the confusion is not that uncommon; the DT has assigned the same DT number, #357, to both Lovely Joan and The Crafty Maid's Policy, though they really are separate songs.  The Highwayman Outwitted (also frequently called The Yorkshire Bite) is also quite separate, though all three songs involve women cunningly pinching horses.  (Actually, the last has a farmer's boy as protagonist at least as often as a farmer's daughter).  Broomfield Hill and Sovay are not related at all.