I have found out from the British Library India Office that they do not have a record of the marriage of Caroline Judith Weiss and Henry Richard Hughes. If anyone had an easily found record, they would. Considering the original information was found in the 1853 Bombay Almanac and not from marriage records held in Bombay, this information has presumably been lost along the way.
So how do I confirm it is the Caroline I'm looking for? Unless I can find a living relative of her sister Adelaide, who may or may not be able to confirm that Caroline married and returned to England, the only option I have is information from her death record. I looked up FreeBMD which gave the details of her death - "HUGHES Caroline J 72 Bath 5c 351" for the April-May-June quarter of 1905. Before going to the extent of ordering a death certificate from that record I looked up the General Register Office (GRO) information to see what details I might get on the death certificate. Unfortunately, for deaths before 1969 there is no information about the date and place of birth recorded - it only shows the age of the deceased, which in this case was 72. I hadn't noticed that before... 1905 - 72 = 1833. 1833 is the year that the Caroline I am looking for was supposedly born.
So whilst this doesn't confirm it, this adds to the circumstantial evidence I have that this is the Caroline Weiss I am looking for. And that's sufficient for me at this stage, unless further information comes to light. But I'm satisfied now with what happened to her - she was born in 1833 in Liverpool, Lancashire, England, to Benigna and Charles Weiss, went with her family to India for her father's work (he was in the British Army), was orphaned in India when both her parents died in 1845, she may or may not have returned home to England for schooling, but then she married in Bombay in 1851, had a few children there in India, returned to England, had one or two more children, and settled with her husband and surviving child(ren) in Walcot, Bath. She lived there until she died in 1905, aged 72. From what I have found, only one of her children, Marion, survived her, and she possibly didn't marry, so that means it is unlikely that there are any descendants I can contact or who would be researching their family history. Which is presumably why this information has remained hidden for so long.
I am considering ordering a copy of her will though, to see what new information that holds...