Excel Power Query Grouping list

Hi,

I'm trying to group an extracted list, my starting point is ;

= Table.Group(Source, {"Product"}, {{"Count", each List.Sum([Sales]), type number},
{"St Dev" , each List.StandardDeviation([Sales] ) } , 
 {"Alll", each _, type table }, 
{ "Who sold what" , each Text.Combine( List.Distinct( [SalesRep]),", " )  }} )

which I am then re grouping so I can rank them, I've attached a work book with three queries, one is what I want but it has a lot of steps which I've been trying to reduce, the problem is the 'who sold what ' column which I can't access, you will see what I've been trying in query two, all I can think is it's because there are more than one value but i can't figure a way round it.

Richard.

FURTHER CLARIFICATION IN POST#6