There are Radfords in gloucestershire to add to the confusion! but could not find Agnes or Elizabeth.
Have found details of James Dust joining up, Must have joined up in Bristol, Queens Square given as place, (there is a Queens Square in Bristol), place of birth given as Iron Acton, joined 18.12.1827, and went to the East Indies in 1828. Might have met Agnes there, but could not find her birth.
The Catherine Radford you found on census could have been a widow.
Several trees on Ancestry but it would need more research to establish details as some of the entries don't seem to tally.
e.g. some say son Edwin born England, not so, and another child listed, no name, but could not find registration of birth or death.
Hope this all makes sense and is of help.