British slang from the 1950s thought to have originated in East Anglia and meaning a lesbian. The word oonch is thought to have derived from the dialect pronunciation of 'conch' and was used as a slang name for the vagina due to the resemblance of the opening of the female genitalia to the opening of a conch shell. Thus a lesbian became an oonch fancier.
"Ah! I wouldn't mind a bit of that!"
"Forget it boy! She's an oonch fancier."
A door wall is a sliding-glass door or patio door. The term is yet another example of banal Michigan vernacular, where in the residents latch on to company names, trademark names, marketing terms and product names from local companies. The terms become embedded in the local vocabulary and eventually become accepted as actual valid words and phrases. In this case the term comes from Wallside Windows in Taylor, MI (a large window manufacturer), where 'door wall' is their created word for sliding-glass door.
"Bob! John's gonna bring over them doorwalls from Wallsides on Tuesdee afternoon 'round two-thirty. Get 'er done!"