In the poem "This be the verse," Phillip Larkin presents a very negative view of parents:
They fill you with the faults they had
And add some extra, just for you.
One might want to deduce from this that Larkin had a miserable childhood and a poor relationship with his parents. However, in an interview conducted in the Paris Review, Larkin stated: "My childhood was all right, comfortable and stable and loving."
I was not able to locate the article that you mention about the relationship between Larkin's parents.
It could be that Larkin holds no particular grudge against his parents; rather, he means to say that we all inherit faults from our parents, who in turn inherited their faults from their parents.
If this doesn't sound very optimistic, you must remember that Larkin is not a very optimistic poet.