I'm replying to a very old post here. But even if John has already solved this issue, it may be of interest to others searching that find this page.
So, John, you're right to be suspicious. If you check the 1861 census then you'll get even more suspicious. Because in that census Thomas' age is given as 61 and Sarah's as 62.
Now would any woman who is 2 or 3 years younger than her husband ever give her age as a year older than him? I've seen enough cases of the inverse, to claim to be younger, but older, really... This isn't just forgetting, or rounding that only applies to to the 1841 census. It's just plain unlikely.
Especially when there is another Sarah Broadhurst that was born in Marple in 1799 which resolves the issue.
Now the consensus view of existing family trees on Ancestry all favour the same Sarah Broadhurst that you chose. But I am convinced that they are wrong. The problem is this.
If you search for Sarah Broadhurst, 1799, Stockport, Cheshire (as the marriage certificate) or Marple, Cheshire, then you won't find her.
Because though she was born in Marple, she was baptised in Marple Bridge, Derbyshire at the Mill Brow independent church on 22 Feb 1799. Her family home was Owl Clough, or Old Clough at the south end of Marple.
Further more the index that Ancestry uses has her name as Broadhirst with an I, not a U, and misleadingly lists her father as Broadhirst.
All of this is enough to throw off the the always taciturn Ancestry search mechanism, even if you do make it through to the non com registers.
However there is a third party transcription of the whole register available which lists the father as blank. Mary Broadhurst was her Mother's name. And not to put too fine a point on it, I believe that her mother was born a Broadhurst and never married! The transcript also specifies Sarah's place of birth as Marple on 2 Jan 1799.
Just to tie the whole thing together, each of Thomas and Sarah's first 5 children including John (your ancestor) and Charles (my ancestor) where also baptised at Mill Brow independent in Marple Bridge, Derbyshire. In each case it specifies place of birth as Marple, and in a couple of cases specifies Old or Owl Clough, Marple.
Finally note that the whole of the Mill Brow baptism register only lists 6 Bowdens but 147 Bodens. I think all of the above entries are listed as Boden, but I think that this is simply the minister's preference.
Old or Owl Clough is now a well preserved listed building. Immediately adjacent to the house there is a (listed) road bridge over the Macclesfield Canal which is actually called Broadhurst's Bridge.
Maybe John Bowden found all this years ago, But I hope it is useful to some future seeker.