needhelp88: ...I spoke to someone who said that in the small print when you apply for an overdraft it states that Natwest may review and remove your overdraft at any time...
Would be better if you created your own thread as it refers to Natwest, the original thread referring to Lloyds.
I can't give you quick advice for Friday but you should obtain a copy of the account terms and conditions and see exactly what they say. I cannot speculate but on the face of it I am surprised there was no notice. Can you think of any obvious reason in your financial circumstances which might have caused this? Is it something they have ever raised with you previously?
Regarding what you were told, you do not need to take anything said by a bank employee as correct unless it is contained in the final response letter to a complaint, so look out the Natwest complaints procedure and get ready to submit a complaint if you find what has been done to you or said to you is not 100% in accordance with the account terms & conditions.
Later edit.
Refer to Clause 6.1.2 of the Natwest Terms & Conditions and decide or find out what grounds Natwest cite for not giving 30 days notice (and what grounds Natwest cite for the verbal explanation you were given referring only to part of the applicable clause).