### Clue: Well-established journalist perching on low chair (4-6)
### Answer: DEEP-SEAT ED 
 ### Explanation: Definition: Well-established
 An ED(abbrev. for "editor"/a journalist) who is perching on/sitting on a DEEP(low as with a person's vocal pitch) SEAT(a chair, for instance) might whimsically be called this – a construction similar to "an upper-class twit".
Defn:  …/deeply ingrained.