Question time #137 has been answered near enough for me.
It is indeed the weight at the front end of a Rotorway skid. In this case it is the Exec 162F ZK-IGH2 (c/n 6632) as recently registered to Jet Exec NZ Ltd. Note the Solar turbine engine !
So one anonymous fish has been despatched to Anonymous - enjoy.
Booby prize goes to CMM for being close - but not close enough.