Steph,
BINGO!?
I have found a Caroline Weedon aged 15 in the 1841 census in Rickmansworth residing at Water Lane and quite probably the mother of the female child born in 1845 in the Rickmansworth Workhouse. Caroline is living with Elizabeth Weedon, 55, rag cutter, (probably her mother) in the home of the Thomas Birch family. Thomas, a brewery labourer, and Martha, his wife, are in their mid 40s and have 4 children.
Is this of any help?
Peter