Hi Dot ...
Confirming the marriage from the OFHS's Oxfordshire Marriage Index (1538-1837):
08 SEP 1718 - Paul CASTLE (of Lyneham) to Mary WHITER (of Milton) at Shipton-under-Wychwood
Looking for Paul's parents, I checked for any CASTLE marriages in the 20 years up to 1693. There were four - two at Deddington (both 1679), S. Hinksey (1688) and Clanfield (1690) - but none "conveniently" located near Lyneham or Shipton!
The are no separate PRs for Lyneham - they are included in those for Shipton-under-Wychwood, so you may need to search these for Paul's baptism.
Pennie