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