The existence of this mare is dubious, her place in pedigrees being derived from a source in an advertisement in Heber's Racing Calendar for 1753 for a stallion sired by Bolton [Old] Starling, which states that his 4th dam was a Helmsley Turk mare. Although the Stud Book of Sir James Lowther confirms this pedigree, his stud book contains only a few original entries of Sir James's own horses, with most of the entries appearing to have been copied directly from contemporary calendars, thereby perpetuating errors in the calendars into his manuscript. A number of errors are immediately discernible in the Lowther Stud Book.
However, the pedigree of Starling attested to by his owner the Duke of Bolton states that his 4th dam was by Bustler, which given its provenance is far more likely to be accurate
The Foundation Mare of Family 24 should therefore be a Bustler Mare, not this Helmsley Turk Mare which probably did not exist.
See research at bloodlines.net:-