Count unique items per client

Hello all,

I have a list of names, downloaded from client software, and then a manually maintained list of names for each, which aims to group clients with different names but the same ultimate beneficiary. Sample attached.

I am looking for a formula which will tell me the number of unique names in col B per name in col A, desired result given in col C.

So for 'APHANE - ARUP JV', result is 1 as all names in B are the same, but for 'APHANE CONSULTING CC' result is 2 as there are 2 different names in B.

I've done this in the past with a pivot table, but it was messy - perhaps I was missing a trick, can anyone offer a solution?

Thanks
Rich