well that was my understanding-but here two sets of banns were read, six months and three months ahead of the wedding
I found one where 2 lots of banns were read 4 years apart same parish in 1879 and 1883, they were shown as married 1881 census and their marriage is dated 1883.
One oddity is the male's 1st christian name was Edward 1879 and Edwin 1883, same middle name each time.
On a different note here I was thinking no need to buy these Greater London marriages from the GRO anymore and then I find a 1839 marriage that is half destroyed.
There's also a few marriages I haven't located on Ancestry.
Mick