Lynne,
If you put:- "An Archaeological Desk-Based Assessment for Broadoak Quarry, Northumberland" (without the inverted commas) into Google search, you will find a PDF, which, while not dealing directly with Ebchester, has quite a bit of information about the area, including some passing references to the mills. There are several old publications to be found from Google searches which include some history of Ebchester, but with only passing, if any, reference to the mills.
The two headstone inscriptions below are the only ones I have come across, so far, referring to the Wardles. I haven't yet totally completed the headstone transcriptions for Ebchester but I'm reasonably sure that these are the only two there - the ones covered so far run from the late 1600's to the present. Sorry I couldn't give you more information.
In Loving Memory of
JOHN WARDLE,
the Mill Ebchester
who died August 27TH 1898
aged 76[?]* years.
Also NANCY his Wife,
who died FebRY 17TH 1869,
aged 46[?]* years.
[The second digit is obscured by erosion and could be a 5, 6 or 8.]
In Loving Memory of
WILLIAM WARDLE,
the beloved Husband of ANN WARDLE, of Ebchester,
who died FebY 7TH 1901, aged 55 years.
Also NANCY ISABELL, their Daughter,
who died April 23RD 1879, aged 7 years.
Also ALFRED STRATTON WARDLE, their Son,
who died April 20TH 1889, aged 1 year.
Also JOHN WILLIAM WARDLE,
their Son and beloved Husband of BARBARA WARDLE,
who died DecR 11TH 1912, aged 39 years.
PatB