Shiny decorated Londoner in pink argyle pants (6,4)
I believe the answer is:
pearly king
'shiny decorated londoner' is the definition.
'pearly king' can be an answer for 'londoner' (I have seen 'Distinguished Londoner' mean 'pearly king' so perhaps 'londoner' could also mean 'pearly king'). I am unsure of the 'shiny decorated' bit.
'pink argyle pants' is the wordplay.
'pants' indicates anagramming the letters (UK informal term for 'nonsense' or 'rubbish').
'pink'+'argyle'='pinkargyle'
'pinkargyle' is an anagram of 'PEARLY KING'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for pearly king that I've seen before include "Fancy London trader" , "Regal costermonger" , "Distinguished Londoner" .)