472kHz WSPR - a new DX record for this season

Last night I was spotted by DH5RAE (995km). This beats by 2km (!!) my previous best on 472kHz TX record this season.  Not bad for 5mW ERP and an earth-electrode "antenna" in the ground. So who says you must have lots of power and big antennas on 472kHz?  I am sure with a larger antenna and ERP I'd get much further, but it shows you don't need this to get useful results. My grounds are about 12m (if that) apart. I need to work out how many stations have spotted my 472kHz WSPR this season. There have been 17 unique station spots of my 5mW ERP in the last 2 weeks.