I thought I had something re marriage but not sure:
Free BMD has 1858 marriage for a Sarah Bridgewater - Cleobury Mortimer district which is the right one for 1841 census- there is a groom missing but I have called myelf to check full index to match a James Smith to no avail!
added;
this is possibly Sarah in 1851 - as Bridgewaters. The age is different to the 1841, 1861,1871 so again you probably have this too.
HO107; Piece: 1985; Folio: 34; Page: 28
Thanks Heywood,
I have already seen all of these.

The name Bridgwater is variable it can have an 'e' in the middle or could be or have an 's' on the end or both!
The name on my Grandmothers and her sisters birth certificate is definately BRIDGWATER without either e or s.
I also checked that marriage on FreeBMD and like you checked the relevant Quarter's Smith's.
There is a John Lambert with a wife Sarah on the 1861 census RG9; Piece: 1846; Folio: 88; Page: 14 living in the Cleobury Mortimer Reg Dist with 3 children, the oldest child being Mary, birth reg Mar Qtr 1859, so I would say that this accounts for that Sarah.
Cheers
Graham
What is also puzzling me is the fact that James smith was supposedly born in Rochdale Lancashire - Sarah in Shropshire and in 1861 they are living in Clerkenwell Middlesex with a child born in Scotland

I know that this branch of my ancestors were all Navvies and assume the change of places are due to railway construction.