Upon clicking New Observation and adding a child's name, the Support Ideas that you have previously picked for this child will appear at the bottom of the screen, this is as a reminder to you that there are outstanding aspects. 

To clean up the these support ideas, go to the Child's Profile page via the Dashboard.

Scroll below the EYFS summary table to the Observations and Support Ideas section.
You will see a list, those with a coloured circle on the left have been observed and can be archived by clicking X.

The grey ones are yet to be observed, so can stay in the list.

Note: The parent will only see these ideas when first selected on an observation.