I have searched FreeBMD
https://www.freebmd.org.uk/cgi/search.pl but couldn't find a marriage for John Mork (1907). These BMD's aren't complete yet.
I did find this on the Electoral Registers which could be John Mork (1907). If he had been married, his wife's name should appear in the household as well.
1959 Liverpool Electoral Registers
Polling District No. 138 FN. Princes Park
109 Park Road
Pettersen, Lilian
Pettersen, Clifford
Carrol, Denis
Mork, John
I was wondering if the Pettersen surname is connected either as a family member or, did Rolf Pettersen and John Mork (1907) serve together on various ships.
Lilian Pettersen nee Duffy appears on various Electoral Registers, but this one she's living with her husband Rolf H Pettersen.
1961: 142 Halewood Road
Duffy, Mary Alice
Pettersen, Rolf H
Pettersen, Lilian
They marry
Marriage: 1944 Liverpool, Lancs
Rolf H Pettersen & Lilian Duffy
This is Lilian Duffy before her marriage to Rolf Pettersen:-
1939 Register: 32 Quarry Street, Liverpool
John Duffy, 14 Apr 1876, Scrap Metal Merchant, Married
Mary A Duffy, 5 Oct 1880, Unpaid Domestic Duties, Married
Lilian Duffy (she married a (?) Petterson), 12 May 1919, Hooper Hosiery Worker, Single
This is the burial of John Mork (1907)
BURIAL
Name: John Mork
Age: Adult
Record Type: Burial
Death Date: abt 1987
Burial Date: 16 Sep 1987
Burial Place: Merseyside, England
Cemetery: Everton Cemetery
Cemetery Section: Church of England
To me, it looks as though John Mork (1907) didn't marry.
This is Catherine Ellen Mork's Will
WILL:
Catherine Ellen Mork of 12 Bridle-avenue Seacombe Wallasey Cheshire widow died 10 October 1948 at 56 Church-road Birkenhead Probate Liverpool 3 November to Albert Edward Orm chief storekeeper. Effects £69 9s. 10d.
The Pettersen/Duffy surnames may have nothing to do with your Mork family, but thought I would just "throw it in the pile" of information.