Just in case anyone else has looked at this thread, the following is my breakdown of one of the formulas that were suggested. It may help unravel the complexity (well I found it complex

)

*{=IFERROR(AGGREGATE(15,6,(1/(Alphabet_Column=Input_Value))*Number_Column,ROWS(A$1:A2)),"")}*
AGGREGATE is a function that returns a list (or lists in this case) of values (an Aggregate - obviously) based on options specified by the first numeric values. First is the function, second is the option. In this case it is asking for SMALL (15) and Ignore error values (6)

Let's take the formula bit by bit:

*(Alphabet_Column=Input_Value)*
will return an array of True;False;False;False;True etc

*1/(Alphabet_Column=Input_Value)*
will create the following

1;Div0;Div0;Div0;1

In the meantime this

*Number_Column*
will return an array of 1,2,3,4,5,

so

*(1/(Alphabet_Column=MrE_Input_Value))******Number_Column
will create the following

1;0;0;0;5

Once copied and pasted into the Results column each separate row is displayed according to the

*ROWS(A$1:A2)* element of the formula which is a neat way of generating an accumulating number.

Thanks again to both of the respondents. Learned a lot this morning.