Hi Carole63,
A little info to start you off:
This looks like your grandparents marriage:
Marriages Dec Q 1919   
Bowron    Mabel    O'Toole    Stockton    10a   162    
O'Toole    John    Bowron    Stockton    10a   162
It would appear that they had 10 children born between 1920-1937     all in Stockton (your dad being child number eight)
All this info can be found using this website:
https://www.freebmd.org.uk/cgi/search.plThere is a Mabel O'Toole (birth year 1896) death registered in 1979 in Cleveland Yorkshire 
and this birth registration (year of birth matches year of birth on death reg for Mabel O'Toole):
Births Sep Q 1896  
Bowron    Mabel   (mother's maiden name Robins)      Stockton    10a   50     
This looks like Mabel Bowron 's baptism:
Mabel Bowron
Name    Mabel Bowron
Residence Place    Stockton-on-Tees, Durham, England
Christening Date    01 Jul 1896
Place    St. Thomas', Stockton-on-Tees, Durham, England
Birth Date    11 Jun 1896
Father's Name    Thomas William Bowron
Mother's Name    Rebecca
Marriage for Thomas and Rebecca:
Marriages Sep 1871
Bowron    Thomas William        Stockton    10a   109    
Robins    Rebecca         Stockton    10a   109      
1901 census link for the family (Mabel recorded as Mable (if you click onto the name Mable Bowron  the full record will appear):
https://tinyurl.com/yamcrkc8This info is from this website:
https://www.familysearch.org/searchYou can use now use this website and the one posted above to see if you can work back through the years to find more on/of your ancestors).