Philistinism is a derogatory term used to describe a particular attitude or set of values. A person called a Philistine (in the relevant sense), is said to despise or undervalue art, beauty, intellectual content, and/or spiritual values. Philistines are also said to be materialistic, to favor conventional social values unthinkingly, and to favor forms of art that have a cheap and easy appeal (e.g. kitsch).
Philistinism affords a contrast to Bohemianism, as the character of a smugly conventional bourgeois social group perceived to lack all the desirably soulful 'bohemian' characteristics, especially an artistic temperament and a broad cultural horizon open to the avant-garde. To the chosen few, the 'Philistines' embodied a smug, anti-intellectual threatening majority, in the 'culture wars' of the 19th century.

Nick, are you being deliberately obtuse?
I was not requesting a definition of a Philistine, but rather what the relevance of Matthew Arnold has in regard of Ned Sherin.
Care to enlighten me?