Just got a final confirmation from the banking ombudsman today;
If you are a joint signatory on an account (including business accounts), the other party(s) can remove you from the bank account and the bank has no obligation to inform you of this event.
That's it - straight forward and simple. You have no expectation of being notified if your access to your account changes.
So - if you are in the situation - don't assume you are safe.
The nasty back twist - if you are in a two person, joint signatory situation, then because after your removal the signatory is changed to single person, then you have no legal recourse to be added back - other than straight out litigation or criminal complaint.