Payments on Mondays

Hi, I was reading through your comments and this is quite interesting and would just like to comment further, I have until recently Banked with NATWEST and I always had my Money paid in for a Monday however it will show on Bank Statements as being paid in on a Mondays date however the funds were available to withdraw using an ATM on a Saturday because following discussions with NATWEST certain Banks computers do not operate on a Monday therefore they can’t credit in on a Monday so it would either be a Saturday or wait til the Tuesday.
However I am now worried as I no longer Bank with NATWEST but NATIONWIDE so will be intrigued to see when I be able to access my funds.