Hi Sue - I do not think I had seen that particular connection before.
But according to my database the Ann Quick who married John Davy at Ludgvan in 1770 was the following:-
Ann d/o Richard and Elizabeth Quick bp. 24th July 1748 Ludgvan
Richard Quick married Elizabeth Row 20th October 1743 St Buryan with Richard having been baptised at Towednack in 1718.
To support my own findings I will add a couple of items for you.
John Davy was baptised at Zennor 11th March 1743 s/o John Davy and Sarah (nee Prous).
I believe this was the second marriage for John Davy snr and that he was probably the same man who married Duins Renawden at Zennor in 1731.
I have not found a burial for Duins but it appears Sarah may have been buried at Zennor 21st June 1746.
The following children for the elder John appear at Zennor:-
Elizabeth d/o John Davy bp. 17th September 1733
Margaret d/o John and Duins Davy bp. 3rd January 1736
Sarah d/o John and Sarah Davy bp. 2nd May 1742
John s/o John and Sarah Davy bp. 11th March 1743
John is not recorded as being widowed when he married Sarah Prous at Zennor in 1741 however the known data supports the fact.
John and Ann (Quick) Davy had three children that I am aware of (all at Zennor):-
John s/o John Davy bp. 25th January 1771
William s/o John Davy bp. 10th March 1773
Richard s/o John Davy bp. 11th February 1776
The following may also belong:-
Thomas s/o John Davy bp. 29th July 1784
Elizabeth d/o John Davy bp. 12th July 1785
John Davy of Boswednack age 75 was buried at Zennor 11th June 1819
Ann Davy of Boswednack age 83 was buried at Zennor 21st January 1831
The age recorded for Ann when she was buried would be a match for either of the two Ann Quicks in question.
However I think the fact John and Ann Davy used the name Richard for their third son is a likely pointer to Ann's father.
Neither William nor Richard are names appearing in the immediate known family of John Davy (he had three sisters) but they can certainly be explained in the family of Ann Quick with her father being Richard and eldest brother William.
CT