Looked at the bottom of my screen and there's brown lines like a rear demister. Does that mean I have a heated front screen and also if so, how do I work it?

Not that I know of; if it was heated there'd be very fine elements running through the whole of the screen like on FORD's etc...

As above, you would see darker squiggly lines if you look close

Not a full screen no.

It's just the area around the wipers that is heated to unfreeze them from the screen in cold weather. Operation of the element is carried out automatically.

Ih that's cool. I assume the heated mirrors work off the rear demister switch?

Ih that's cool. I assume the heated mirrors work off the rear demister switch?

Yes mate

Mirror heating is outside temperature dependant & a bit more complicated than you might expect.

Here's the blurb:

Mirror Heating

Mirror heating is controlled by the peripheral modules in the doors. The
heating function is active as of terminal 15 (ignition lock position 2). The
activation time is dependent on the outside temperature.

The general module receives the outside temperature from the IKE via the
K-bus and determines a cycle time for heating operation. This time is
transferred to the peripheral modules where it is carried out. Heating is no
longer active at an outside temperature greater than 25 ^oC and it is
switched on permanently at a temperature lower than -10 ^oC