@KeithBarrows, if you are using instance methods, always use the .Enqueue<T> method overloads:
// This is for instance methods
/// Place [Queue] attribute to the IJob.Execute method
BackgroundJob.Enqueue<IJob>(x => x.Execute("payload"));
// This is for static methods
BackgroundJob.Enqueue(() => Program.Main());
Never use the following construct, as it even does not make any sense, because of unnecessary creation of the Job class instance.
// Don't do this at home
var job = new Job();
BackgroundJob.Enqueue(() => job.Execute());