Sons

"Sarcastic sons slam" -> alliteration/sibilance

"of Cardiff outskirts where, once captured acres played" -> looking back on how he was in his youth (when he was a son not a father)

"Now my son is like that, altering every day", "I was like that; also like" -> his son is now acting like how he used to -> links to Larkin's 'Dockery and Son' - how father and son are both alike in their youth

"At the frontier of Nowhere order and chaos clash" -> 'frontier of Nowhere' could be referring to youth and wanting to find yourself

"and being adolescent was both prim and brash" -> juxtaposition of two opposites/oxymoron - 'prim and brash' highlights changing emotions

"strange a London door should slam and I think thus. of Cardiff evenings" -> persona is here using opposites to describe his son - a reference to his son not knowing who he is yet? -> "wrongly named" -> "Awkward Anglo-Welsh half town, half countryside"

"son, you are like that and I love you for it. In adult rooms." -> persona could be empathising with his son as he reminds him of himself when he was young - maybe makes him think of the relationship he had with his father

"Too soon maturity will switch off your night thrust fake electronic roots, the nameless becoming wrongly named and your savage darkness bright." -> this here could be the persona looking back with perspective - his warning to his son that this will happen to him too like it did to himself 

Looking back with perspective could link to Larkin's 'Reference Back' and 'Love Songs in Age'

Rhyme Scheme -> C+D and 6th line of stanzas 2,3 and 4 -> Stanza 1 -> D+F -> the pattern begins irregularly - could represent his son's adolescence and changing/erratic emotions?