Data counting unique values based on different unique values

Hi,

Not sure if this can be done but;

My main unique entries that I want to record from are Column M.

Previously I have been filtering the whole data by a unique value in column M, then from there I have to filter by a unique value from column K and once that is done I manually count the unique values in column D.

By doing that I can work out the number of unique values there are in column D in relation to the unique values selected in M and K. My problem is, I have about 10 different unique values in column M and from each of those unique values I need to work out the count in column D for every unique value in column K. This involves a lot of filtering and manual effort.

Is there an easier way this can be done? Any help would be much appreciated. I've attached a data sheet.