Averil you were doing what Eric critiqued in assuming what you had to prove;

Finally found John Looney's wife Margt's family name written in a deed - NSM May 1788 83 - the 2nd of John Looney's mortgages on his 3 fields dated 12 May 1788 and names her as Margt als Hudgeson - in the later additional mortgage to John Kerruish John Looney noted as of Bwoiltrowan

also looked at marriage reg - he is as I noted only given as John Looney not John Looney junr however he signs his name (somewhat poor hand) but same signature appears as a witness to marriage of Wm Looney + Mary Corkil on 7 Dec 1776 - margt marks with 'x'
Not sure if this links John + Wm Looney

Looked at baptisms of his 1st 3 children - no additional info given in register