Converting Monthly to Weekly

I have a set of monthly sales for different businesses and want to phase this to a weekly budget but its not as simple as dividing by number of weeks - the weekly view needs to take into account working days (Mon-Fri) and also public/ bank holidays for UK and EU. I have tried a few different models but failed. 

My current monthly format layout is also follows :

column A : business name

column B : account codes (sales, etc)

rows : month (ie Jan - Dec)

Any help would be much appreciated.