I am interested in the Dalgarnos. I found 3 marriages of a William.I only have births up to 1922,from London record office,so can't give you a reference.
Your best bet would be to get your dad's birth entry looked up.Ronald James should be easy to find within a 3-4 year span.The actual index entry sometimes gives the mother's maiden surname (not every year).
I assume his birth certificate is not available,nor his marriage certificate???
Keep in touch,as I may be able to fill in some holes later on,as I go to the record office fairly frequemtly.
My grandmother was Barbara Pirie Dalgarno,from banffshire,but in my research I have connected a number of Scottish families to those spread out in England.