Hi Elaine,
Wiltshire has an On-Line-Parish clerk for Milton Lilbourne (Linda Hull). If you contact her she may be able to help you.
If you go to this address and scroll down to the Milton Parish and click on it, it will open where there are some transcripts for baptism, marriages & burials.
http://www.wiltshire-opc.org.uk/genealogy/index.php/parish-directory/item/165-milton-lilbourneI did look but could only find a “Joan” Tarrant baptised 1688 which may be her and mis-transcribed, but I see they only start in 1686 so Jane could have been born before.
Unfortunately her marriage in 1703 doesn’t appear in the transcripts and I see they are incomplete anyway, so its worth contacting the OPC.
It would appear that registers only start in 1686.
Disclaimer - I’m not associated with the Wilts OPC just a user of their services.
Alan