So I took the dipstick out and there was NO oil on it...
Doh! Guess I've done about 1,500 miles since I bought the car, oil at Max on stick at the time... just never thought to check it since... so checked it yesterday and no oil on the stick at all, not even below Min...
Damn, grabbed a can of Mobil1 pronto and it took about 2 litres to bring it back up to Max.
How worried should I be???