The phrase "a long established one" is correct and usable in written English.
It can be used to refer to something that has been in existence for a significant period of time, often implying a sense of tradition or reliability.
Example: "The organization is a long established one, known for its commitment to community service."
Alternatives: "a well-established one" or "a long-standing one."
The practice of paying people for information about celebrities and other people in the news is a long-established one at British (and American) tabloids.
Mr. Graham found the lace at Klauber Brothers, a trimmings house so long established that one of its founders died aboard the Titanic, returning from Europe during a season that was also a big one for lace, according to news reports of 1912.
The format was long established, a one-off hour in which luminaries like Des O'Connor or Lulu gigged for a room of celebrity fans.
Long established as one of the Middle East's finest and best-loved writers, and an ardent advocate of moderation and religious tolerance, Mahfouz's acceptance of the Nobel Prize in 1988 brought him to international notice.
Long established as one of the finest conductors of choral music, Edward Gardner turned his attention to A Child of Our Time for his latest concert with the BBC Symphony Orchestra and Chorus.
Flies are long established as one of the prime models for research in developmental biology, cell biology and neurobiology, but it is only in the past decade that they have been significantly deployed to dissect energy metabolism.
The land loss affects the ecology of the Delta including the related fisheries, and threatens many communities including long established native ones.
Moreover, even if a long-term health risk from abortion ever were established, one would be comparing sudden death in one's childbearing years to affliction with a treatable (and even curable) illness many years later.
Bowser established one of the longest records of support of and participation in the Eastern Fish Health Workshop, having first participated in the third Eastern Fish Health Workshop hosted by Auburn University in 1978.
