Workflow validator to check epic link of certain name is in certain status

[Alex Fox]

Hello all, currently planning our cloud migration as I'm sure many people are and am trying to set up a ScriptRunner validation to check if any issue in an epic has a certain name, then it must be in a certain status. I.e. the Epic cannot move to Status C if the issue in the epic called "Special Issues" is NOT in Status D.

I've been looking at every bit of documentation I can find (and I have to say the ScriptRunner cloud expression examples are WOEFULLY short considering how many people will be migrating to Cloud over the next 12-24 months) and I can't seem to get my head around the syntax for checking issues in an Epic in this way. There's plenty of examples of sub-tasks but these are sub-tasks.

Grateful for any assistance!