G2G: Seeking a source of a Stafford family member

Question

I'm looking for a primary source of a "Lady Dierdre Stafford", B1520, D1576.

Daughter of Henry Stafford 2nd Duke of Buckingham (1502-1563) and Lady Ursula Pole. Barroness Stafford (1504-1570) Daughter of Margaret Plantagenet.

Born Thornbury Castle Buckingham, Died London.

Did she exist, or is she an internet fabrication? I've seen multiple secondary sources citing her but no primary source.

Comments

It looks like an internet invention. He had a daughter Dorothy but not Dierdre or Deirdre, which was not a name used in England in the 16th century. When I searched TNA Discovery for Dierdre or Deirdre, I got zero results for 1500-99. The first results were in the 19th century.

The name is Irish; it became popular after the publication of the poem Deirdre by the Irish poet William Butler Yeats in 1907.