[Merry]

So you are looking for the baptism of this bride:

Marriage: 19 Jul 1785 All Saints, Wigan, Lancashire, England
William Calland - Haigh
Ann Lea - Haigh
Witness: Peter Grimshaw; Gerd. Bancks
Married by Banns by: Page Godfrey
Notes: [Bride signed Ann Ley]
Source: LDS Film 1885689

I don't see why she would be born about 1775/6 because that would make her about 10 when she married! Perhaps you have a burial for her with her age recorded? If you do, are you sure it's the right Ann Calland?

So we are looking for a baptism for an Ann Lea, parents Thomas and Betty (from post #13).

I would expect the issue to be that there are far too many possible baptisms rather than only one in the wrong county and at a date that doesn't work!

I've only looked at Lancs OPC (where I'm assuming you will have looked already) and did ten years either way of 1760. That gave me five matches, so you would need to use your local knowledge to decide if any are not likely geographically and also try and establish what happened to each of these Anns to see if you can rule any out (eg if any of them died young etc).

Baptism: ? Jan 1749/50 St Laurence, Chorley, Lancashire, England
Ann Leigh - Daughter of Thomas Leigh
Register: Baptisms 1709 - 1768, Page 45, Entry 29
Source: LDS Film 93703

Baptism: 8 Jul 1753 St Mary the Virgin, Eccles, Lancashire, England
Anne Lee - Daughter of Thos. Lee
Abode: Pendleton
Source: Manchester Central Library

Baptism: 31 Mar 1754 St Laurence, Chorley, Lancashire, England
Ann Leigh - Daughter of Thomas Leigh
Register: Baptisms 1709 - 1768, Page 50, Entry 8
Source: LDS Film 93703

Baptism: 19 Sep 1762 St Peter, Bolton, Lancashire, England
Ann Lee - Daughter of Thos. Lee & Betty
Abode: Turton
Source: LDS Family Search

Baptism: 6 Feb 1767 St Mary the Virgin, Leigh, Lancashire, England
Ann Lee - Daughter of Thomas Lee
Abode: Bedford
Register: Baptisms 1757 - 1769, Page 110
Source: LDS Film 1885648