Not sure if it's illegal of not (I'll have to ask the vehicle seating team and / or the legal team here at work) but there are other things to consider, such as the immense amount of forwards and side vision you'll lose if you do choose to drive with the seat facing back to front, the integrity of the seat in a crash, it will have been degigned to withstand a frontal impact far greater than a rear end shunt so with the seat 'back to front' it will be much weaker in a front end shunt which invariablyhave the greater vehicle to vehicle closing speeds.