I have had a look at the 1841 and 1851 for Park Street that is listed on the birth cert, there is nobody Dawes or Elliot living in Park Street at those times.
I did however come across a Mary Elliot living in the area in 1841, listed as living with Thomas Elliot, but there was no relationships listed on the 1841, they were both the same age, but could have been about 5 years out as ages were rounded up or down.
This is the 1841 that I found, it could be a long shot, and may be no connection, but it is the same place that Selina's birth was registered.
Estimated Birth Year:
Old genealogists never die......they just lose their census.