RDS instance stuck in Deleting state

Any advise for blowing away an Aurora RDS instance stuck in a "deleting" state.

I was doing some experimenting trying to upgrade a test RDS Cluster which was making no progress. When I looked further the instance had other issues where it wasn't fully started and stuck in a state of "Configuring-enhanced-monitoring" so in hindsight I should have checked this and not tried to upgrade the instance.

As it is just a test database I tried to delete the instance but now it is stuck in a state of "deleting". Is there anything I can do to forcibly blow it away?