Silly question really guys but can anyone tell me what this switch does? Its the one located above the chart light switch near the oxygen mask, i've switched it on but never seen anything.

Ah, yes.... it controls a light which illuminates the captains lap, so he can read maps on his knee.... to view, go to the VC. (F9) and click 'A' to flick to FO seat. Pan across left so you can see the map light switch and turn it on... pan down and back a bit and you will see the captains seat illuminated. Obviously it will help if its dark! The other switch (chart) illuminates the clipboard on the left window frame.

Aha..Thanks for that Drew!