Hi David,
thanks for your help, i think that now i can rule out that they were in Woburn on the 1841 census. Woburn was where all John and Sarah's children were born.
Since i posted the listing i have received the marriage certificate of John and Sarah Garratt's daughter Louisa and it gives John the name of John Dingly Garratt, and the marriage was in West Derby. And i then found a death for him in West Derby Lancashire in 1850.
So they could be living in West Derby for the 1841 census.
The death that you found for Sarah in 1832 could be a good possible.
Thanks again for your help
Best Wishes
Dorothy