AS we've only started the roll out of WDE 8.5, we didnt use the feature at the time, but I've worked with it a little bit more now. We had an issue that if interaction-workspace\display = false on the field then it didnt work. So here's what we have now on the field:
[default]
icon_attribute = 1
send_attribute = CALL_OUTCOME
[gim-etl-mapping]
column-name = RECORD_FIELD_2_STRING_6
table-name = RECORD_GROUP_FIELD_2
[interaction-workspace]
display = true
display-name = Call Outcome Code
read-only = true
And the relevant options for dispostion on the workspace application (or Agent Group):
[interaction-workspace]
interaction.disposition.is-mandatory=TRUE
interaction.disposition.key-name=CALL_OUTCOME
interaction.disposition.value-business-attribute=DL Outbound Dispositions
interaction.disposition.is-read-only-on-idle=false
interaction.disposition.use-connection-id=true
Still going through all the testing but seems to work now.