Sorry but I'm not having any luck with the surname Manona. I see that the marriage was St George Hanover Square. Did Mary Anne give her fathers occupation on the marriage certificate, and who are the witnesses?
I'm having trouble locating Mary Ann on the census prior to 1891, can you please give details.EDITED On the FMP site there is a marriage in Calcutta 1753 name Manona. I know the date is a bit early but there may be a connection.