I noticed no baptism of a wm corlet in Peel (German) in 1775 when I transcribed those years (I may have missed it - however some 'friendly' mormon patron has submitted many corlett entries to the IGI many of which I've found to be mistaken (wrong years, wrong names, guessed parents etc)

The wm corlett baptised in Lonan in 1798 appears to be a singleton entry for father Wm Corlett - I think he may be child of Wm + Elinor Quark married in Lonan (see marr reg on manxnotebook) who went on to have large family in Douglas - there is a 5 year gap between marriage and 1st noted child that would be partially filled by this wm (the Lonan regs c. 1798 are confused + partially missing)