I guess I was just being a bit lazy. What I meant was, do two SUMIFs and add them together and two COUNTIFs and add them together, and then divide the total SUMIFs by the total COUNTIFs.

=(SUMIF(WeeklySummary!BZ32:BZ36,">0")+SUMIF(WeeklySummary!DD32:DD36,">0")) / (COUNTIF(WeeklySummary!BZ32:BZ36,">0")+COUNTIF(WeeklySummary!DD32:DD36,">0"))

Regards