Jonathan is correct, in all previous games if you skipped through the intro screen using a keyboard, then the keyboard becomes the default controller.
So
try skipping these intros using a button on your wheel, the G27 used to be one of the red ones on the gearbox (button 1 or 2), but F1 2015 is one of the group of 4 near the rear of the gear box, the bottom one I think. It might solve the problem
The other real pain is that the G27 uses button numbers, but the menus in the game use gamepad icons, like X,Y, A, B, RB, LB ...... which don't exist on a G27. It makes you think that all they did was plug a G27 into a console when creating this game, and never once plugged one into a PC.
It's so obviously wrong
For other wheels ....... keep trying the buttons on the wheel, one should work for skipping the intros.