With regard to William Couch's birth, there are quite a number coming up for a period 10 years + and - Loveday's birth. On this basis it's rather like trying to find a needle in a haystack!
This link
http://www.stkeverneparishcouncil.org.uk/cms/ might be worth looking at and if necessary contact, in the hope parish records may be held for that period. If so either a birth record of James might help or better still the marriage record of William Couch and Loveday. Have a look at the above and think about emailing them to ask if they hold records.