had a look at those morts I had photos of - you appear to be confused re Charles s/o John - the charles that married Elizth Miller was 1786 and probably grandson of the Charles you think took over Fildraw
There are 4 mortgages
old Mal mort 60 Jno to Wm Kinley, old Mort 80 Jno to Ewan Looney (redeemed 1734),
Charles + wife Margt to aunt Cath Mcylrea(now of Ballaquaile) SSM Oct 1729 36 borrowed £5 on security of land - redeemed 1734 + a 1731 mort Charles to John Bell senr + junr (SSM Oct 1731 60) wch I don't have