Restartable Job not restarting

Having taken some advice from a previous forum post, I'm using 'Debugger.Launch' like so...

public override string Execute()
{
    Debugger.Launch();

..to attach to my scheduled job whenever it is run. I presume I'm using the correct attribute to create a restartable scheduled job...

[ScheduledPlugIn(DisplayName = "MyScheduledJob",Restartable = true)]
public class MyScheduledJob : ScheduledJobBase

but my job isn't restarting when I...

a. ...kill the IIS Worker Process

b. ...recycle the app pool

c. ...set the app pool idle timeout to 2 minutes

If I then call my job directly, its happy to start work and pick up from where it left off, so it appears it's just episerver not asking for it to start again after it stops

How do I simulate a correct restartable situation?