I have managed to get a list of items that use a specific template. I now want to add an Insert option to each of those items.
I understand that I can edit the template Insert options and update the Items but this will remove some custom Insert options that have been added to items. I've looked at the examples here but there isn't one to do what I need to do - so perhaps it's not possible.
If you can't reset the items' insert options fields for whatever reason, you can always use the Insert rules to add or remove insert options with the rules engine.
Note: the best approach for managing insert options is almost always to use the Insert options (__Masters) field on the __Standard values item of the templates. Adding or removing a large number of insert options in this way will affect performance of the Sitecore Content Editor.
To add a rule that manipulates the insert options:
Create a new item of template Insert Options Rule below /sitecore/system/Settings/Rules/Insert Options/Rules
In the Rule field, click Edit Rule to open the Rule Set Editor
In the Item Information section of the conditions list (the left list), click on the condition where the item template is _specific template_
In the Rule description section below, you should see your new rule appear. Click the specific template link and select your page's template
In the actions list (the right list), click on either add specific insert options or remove specific insert option
In the Rule description section, click the specific link and select the template you'd like to add/remove
InsertOptionsfrom and added some different ones. This is why I can't just edit the template
standardvaluesand reset the content