Count data cells with multiple criteria

I'm hoping you kind forum members can help me.

I looking for a formula where I can count the number of cells with data included, depending on criteria from two other columns.

In my example I want any cells with data in column A counted if a "Joe Bloggs" is recorded in column D and there is no data in column K

I've tried to work COUNTIF and SUMPRODUCT but cannot get the formula right for both criteria points.

Any help would be gratefully received.