The point with influences is most young kids in Manchester didnt know the 'Royals ' craze originated in a shop in Richmond 200 miles away that was set up to sell Ivy clothes to london executives not cockney herberts . Kids see someone else at school or down the shops in clobber and decide they want to look like them but the Button down collar shirt is Ivy , Sta prest are Ivy the Harrington is Ivy .. by the time a 'look ' spreads out from a original core group and core shops into high st's and market snides the original source is lost and of no interest to these kids but the facts remain .
As I said:
"Now it was astute clothing retailers who were deciding what items to stock and anyone could go into a boutique and be sold stuff"
As you have written, the original source is lost.
'Harringtons' were originally produced in the north west of England and worn as golf jackets - doesn't that then mean that north west golfers were an influence on skinhead?
I think we are all agreed that some of the clothes we wore were also worn by (or similar to) Ivy Leaguers at various times, it the degree of that as an 'influence' that I'm questioning. Whatever that influence was, we were unaware of it at the time.