The SMI has no marriage for Charles ELMES to Ann.
It does have a couple around the right time and place to other women.
Here's the first at nearby Storrington.
Place: Storrington, West Sussex, Date: 3 Oct 1768:
Subject: Charles ELMES, bach
Spouse: Jane CLEMENTS, sp
And the licence:
Place: Archdeaconry of Chichester Marriage Licence, Date: 3 Oct 1768:
Subject: Charles ELMES, bach 22 butcher otsp
Spouse: Jane CLEMENTS, sp 21 Storrington
Extra Information: SRS 32 ss: C.E.; Thos. C. butcher otsp
Here's the second eight years later.
Place: Kirdford, West Sussex, Date: 29 Jun 1776:
Subject: Charles ELMES, widr Thackham
Spouse: Sarah FOYRCE, sp otp (lic)
And the licence:
Place: Archdeaconry of Chichester Marriage Licence, Date: 18 Jun 1776:
Subject: Charles ELMES, widr 22 butcher Thakeham
Spouse: Sarah VOICE, sp 23 Kirdford
Extra Information: SRS 35 ss: C.E.; Arthur RANDALL bricklayer otsp
Interesting that both men are butchers, and in the later marriage Charles is a widower. If it wasn't for the age in the second licence I'd make the two men identical. I wonder if there was a transcription error there? 22 is quite young to be a widower (but by no means impossibly so with a wife's death in childbirth so common).
Velcro, how sure are you about the accuracy of the mother's given name in the Thakeham baptism register? Although I don't have access to it now, I have in the past looked at a microfilm of the register and from what I can remember it's very hard to read.
I'll have a look at my record of Storrington registers (I don't have those for Thakeham) to see if they are of any help in answering your questions. I'll post any answers I find later.
HTH,
Stovepipe