An interesting debate, but one that is not new.
Take a look at the STAR plates published in the AIP. There you will find that there is data relating to standing agreements. It is called "Descent Planning", and actually stipulates the SA.
To get this data into the AIP was a huge exercise in overcoming some entrenched views of the world. An Air 2000 pilot and an ATCO at West Drayton wrote the paper that presented the arguments "for", and it included the results of meetings with the then Hd of CAP1 (Mike Wildin in those days), as to how to ensure the accuracy of these inclusions. This all came about because of the interface the FMS and the ATC operational environment.
In the case of Leeds, there are no STARs. In such circumstances, it was recomended that standing agreement levels were included in the textual section of the aerodrome entry in the AIP. It was also recommended that certain level restrictions - target levels etc were also published here. Such as FL 270 20< CUMRI, for NOKIN SIDS ex EGCC ( OK I know that it is FL270 25 <PERUP before today, but when the paper was written PERUP was not even a twinkle in PLGs or Lee Boultons eye).
One of the concerns was that flight crews would act upon this information independently from an ATC instruction. At the time I seem to recall at West Drayton, it was a live issue.
Looks like it needs to be reviewed again. Maybe there should be STARs for Leeds?