I think it's all on here:
http://www.gro.gov.uk/gro/content/I was getting so confused! There are two entries for a Jane Harris (within 2 yrs within 2 yrs birth years) for 1861. One is with Henry - the other with a Jane Lawrence (from 1851). She is listed as 'wife's mother' for a William John Godsalve Crosse (!!) and his wife Mary Ann. (There are also 2 entries for him- one with Mary Ann and another as a nephew!)
I looked this marriage up - a Mary Ann Bridger (oh no I thought - another marriage!)
However eventually I found that Mary Ann Backway was married same quarter and year- checked this out with Family Search and it is her!
Jane must be on the census twice- perhaps only staying there a couple of nights.
I'm so glad that it has worked out and hope you get it the certificate.
best wishes
Kath
PS if you go to Ancestry.co.uk and search free BMD there is a link for certificates online besides the one I gave.