Hi,
I've checked the registers for Ospringe (PR), Faversham (PR), Buckland-next-Faversham (BT), and Preston-next-Faversham (BT) and can find no Jane Robinson baptised at any of those parishes at any time between 1720 and 1750.
Also, from my Archdeacon's Transcripts of Teynham, I have the Jull/Robinson marriage showing the bride's name as Sarah rather than Jane. So, I have also checked the same parishes for the baptism of a Sarah Robinson with the same results.
I've also checked the Canterbury Marriage Licences for both the Rev. Robinson's marriage as well as Jane's marriage in 1764 with no success.
If nothing else, at least you can eliminate these sources from your enquiry. Sorry I can't be of much more help.
Sincerely,
Susan