Ok, for those who might know some geography of the region, the highest peaks of the King Leopold Ranges top 900m asl. My mystery site is the highest altitude BOM site in the region at just under 600m asl. I have camped out there in August and its bloody cold haha.
Its the most northerly site in WA to record frosts and does so most winters.
and yes the name of the location has a royal connection.