Hi Sarah,
Here are a few Benjamin Ketleys I have, I'm not saying they are relevant but they might be of some use.
Daniel Katloy of Benjamin & Ann, bap 6 Jul 1743 at Felsted.
Benjamin Ketley of John & Rachel, bap 9 Feb 1751 at Gt Leighs.
Benjamin Kitley of Benjamin & Eleanor, bap 6 Jan 1760 at Gt Leighs.
Benjamin Ketley married Martha Thompson 13 Oct 1789 at Felsted.
John Ketley married Rachel Curtis 26 Nov 1749 at Gt Easton, John of Gt Waltham & Rachel of Gt Easton. I found baptisms of three of their children at Gt Leighs, including Benjamin (above).
Zachary Kettley married Katherine Brewer 16 Sep 1733 at Gt Waltham, no Benjamin involved but it is at least a Gt Waltham Ketley

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By the way I found three other chidren of Benjamin and Eleanor baptised at Gt Leighs, you probably have them but I'll send them anyway. I hope to answer your email tomorrow.
Regards.