I need a formula to calculate the first working day of the month. At present
I am using:

=DATE(YEAR(B9),MONTH(B9),1+IF(WEEKDAY(DATE(YEAR(B9 ),MONTH(B9),1))=7,2,IF(WEEKDAY(DATE(YEAR(B9),MONTH (B9),1))=1,1,0)))

where B9 is today's date. However, this does not take into account bank
holidays (such as 1 January).

This spreadsheet is for use by other users and needs to be as automated as
possible so I don't want to override the date cell if I can help it. Does
anyone have a simple formula to calculate the first working day of each
month, taking into account bank holidays?

Thanks