PQ - Non standard approach to Counting Distinct entries by group

Non standard approach to Counting Distinct entries by group

Country	Registration	Van Type	Date	Valid Journey?		Country	Van Type	Date	Distinct Van	Valid Journeys
England	ABC123	Small	01/05/2020	Y		England	Small	01/05/2020	1	2
England	ABC123	Small	01/05/2020	Y		Scotland	Small	01/05/2020	1	1
Scotland	DEF123	Small	01/05/2020	Y		England	Small	02/05/2020	1	1
England	ABC123	Small	02/05/2020	Y		England	Large	02/05/2020	2	3
England	ZYX123	Large	02/05/2020	Y		Scotland	Small	02/05/2020	1	1
England	DFG991	Large	02/05/2020	Y
England	DFG991	Large	02/05/2020	Y
Scotland	DEF123	Small	02/05/2020	Y
Scotland	DEF123	Small	01/05/2020	N

Code:

---

let
    Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
    Ones = Table.AddColumn(Table.TransformColumnTypes(Source,{{"Date", type date}}), "Ones", each 1),
    Group = Table.Group(Ones, {"Country", "Van Type", "Date", "Valid Journey?"}, {{"Valid Journeys", each List.Sum([Ones]), type number}, {"Distinct Van", each Table.RowCount(Table.Distinct(_)), type number}}),
    TSC = Table.SelectColumns(Table.SelectRows(Group, each ([#"Valid Journey?"] = "Y")),{"Country", "Van Type", "Date", "Distinct Van", "Valid Journeys"})
in
    TSC

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