I chose not to smoke while driving many years ago...
Our car, on the other hand, very occasionally blows a cloud of smoke on first start up after not being used for some time. Doesn't seem to matter whether it's parked on level or sloping ground. Running oil consumption is negligible, so exactly: just leave things as they are, and don't lose sleep over wondering why it happens.

Cheers guys

"It had new oil last week and its only started since then really?"

Is the new oil level correct, or a wee bitty high? Or, was the old oil level a tad low, so that's why it wasn't burning anything before...

And, what grade of oil was used in this recent oil change? As Sam says, a thicker grade - say 20/50 - should smoke a lot less, tho' whether it's advisable during this cold spell is another matter. In general, tho', as an engine wears and tolerances increase, a thicker grade can help fill 'em gaps...