Hi Frank,
I looked for Frederic Walter RUCK in Wellington in the 1879-80, 1878-79, and 1880-81 Electoral Rolls, but without success. I jumped forward to 1900 and found him:
1900 Electoral Roll for Wellington;
#12559 RUCK Frederic Walter, 16 Dixon Street, commission agent, residential
#12600 RUCK Phoebe, Willis Street, housekeeper, residential
1903 Electoral Roll for Wellington, page 231;
#12746 RUCK Emily Louisa, 34 Oriental Terrace, domestic duties
#12747 RUCK Frederic Walter, 219 Willis Street, commission agent
#12748 RUCK Phoebe, Willis Street, domestic duties
The term ‘domestic duties’ might (or might not) mean the individual was married, so it’s safer to assume he was not married to Phoebe RUCK until you have independent confirmation. It appears unlikely.
Regards, riley