You've had a bit of a runaround, but it's been a good few years since they were referred to as Premium Account Managers in NatWest. Feel free to pm me if you like and I'll happily clear up your details of who and how to contact.
If you want to know who your NatWest bank manager is, go in and ask them. Every branch has one. If you want to know who your account manager (or personal adviser) is, go and ask them. If you want your branch to stay open, use it. Why not combine the lot in one go and make an appointment to see...