Following further research I now think that the mystery surrounding the missing records of the marriage of Henry Elliott SMITH and Isabella Anne BRABAZON is now solved, thanks to all who participated.
Isabella's father, Rev John Vignoles Brabazon was Church of Ireland, while Henry Elliott Smith was a Primitive Methodist. Apparently that was not a good basis for a marriage. Coming from a secular country I had not previously appreciated the significance of religion in family matters. It appears that Rev John may not have approved of the wedding of his daughter to Henry Smith, and that she therefore may have married secretly under the name of Isabella Browne. It is possible to reconcile the differences between the official records of the children and our family records, if we allow for family names to be derivations of actual names, and if one birth is put in a different sequence. There is still some way to go to be certain, but this thesis seems to be the most likely explanation.
I am still seeking information on the groom's father.
Thank you to all who participated for your greatly appreciated assistance, and to this wonderful forum in general!
Terry