I'm super close, I've got the modals working, saving the value back into umbraco ok. Just stuck now on editor configuration validation. I've got a couple of fields that need a value ie api key. I've created a ValueValidator but this only seems to fire when the property is saved in umbraco. What I'm looking for, is some way to validate the property config when setting it up originally? With the old angular way, I could do this:

prevalues: {
                fields: [
                    {
                        label: "YouTube API Key",
                        description: "Please enter your YouTube API Key",
                        key: "apikey",
                        view: "requiredfield",
                        validation: [
                            {
                                type: "Required" 
                            }                        
                        ]
                    }
           ]
}