Hello again.
I think I have found the marriage I was looking for in my original post.

On Freereg at Mistley 23rd Feb. 1789
Philip Ho(px)ey bachelor of Thorpe-le-Soken to Elizabeth Palmer. Elizabeth Palmer had relatives Jonas and Jonathan Palmer. Philip and Elizabeth had two children named Jonathan and Jonas so I think I am on the right track.
I am still looking for this Philip Oxley's baptism around 1758. It was not recorded at Thorpe-le-Soken but I think the nearby parish of Great Bentley may hold the answer. According to Freereg there were four marriages of one or more Philip Oxleys, with various spellings, at Great Bentley:
Philip Oxey bac. to Sarah White 1758
Philip Oxe to Sarah Olive 1762
Philip Oxe wid. to Mary Griggs 1768
Philip Oxley wid. to Sarah Clark 1792.
If someone has access to Great Bentley baptisms and burials register could they see if a Philip Oxley around 1758 was baptised there please?
Thank you for reading this.