How do I compose a formula that looks at values in column BP that are from the previous week (The week always starts on a Monday. So for today,(being 4 December) I want it to count anything from Monday 26 November to Sunday 2 December inclusive please. On a Monday it needs to automatically change for the prev. week. So on Monday 10 Dec, it will automatically change the data to Mon 3 Dec-Sun 9 Dec.