Hi, can anyone help with this odd oil burning issue please.

My Bravo (1.4 T-jet 150 bhp) has a random oil burning issue. On occasions when you change gear or set off it will put out a large blue oil burning cloud from the exhaust. It does it just once, as though it has cleared oil from somewhere, then its ok again. It can run for months without that happening, sometimes it can do it 3/4 in a week.

Any ideas on what might be happening?

Thanks