Update: I have drained the old oil - looked ok - had a dark grey color - looked like slightly used engine oil.
I re-filled with 10W30 oil - about 700ml - should be 750ml.
Ran for 2 mins - blew some white smoke for about 1 min then eased up to almost normal.
I stopped motor to check oil level and when I removed fill plug white ( almost ) milky oil poured out of fill hole so plug straight back in.
Left for 10 mins and now can check oil level and oil no longer looks milky inside fill hole.
Any ideas appreciated.
