SQL Server insert missing record with select distinct or left join

I have a table where is some case we are missing the location record for location = 'WHS1'. You will notice the bottom 2 "TCODE's" do not have a location = WHS1 record

I was thinking of doing a select distinct on TCODE InvYear and to get unique records then checking to see if the Location 'WHS1' NOT Exist.

I'm very green at this that you for any help

TCODE   InvYear Location    StartingInv Adjustments Damages EndingInv
NY530-1 2015    BRX         625         NULL        NULL    709
NY530-1 2015    LAN         365         NULL        NULL    365
NY530-1 2015    WHS1        432         NULL        NULL    442
NY530-2 2015    BRX         309         NULL        NULL    413
NY530-2 2015    LAN         94          NULL        NULL    96
NY530-2 2015    WHS1        1310        NULL        NULL    1344
NY547-1 2015    BRX         0           NULL        NULL    0
NY547-2 2015    BRX         0           NULL        NULL    0

via Chebli Mohamed