Driver's side is the intelligent choice. IF you want to drive on the continent and use it for shade. Oooh it's lunch time, let's stop at the side of the road, stick the awning up and sit in the shade. Bugger, The awning opens into the traffic. Wish we'd put it on the opposite side.
End of. This also influences the choice of wheel carrier too. If you go driver's side then the wheel carrier swivel needs to be passenger side or else your spare will open right into the middle of your awning. Also this way you can keep your std UK fog light as it's not obscured. See, I've though this through. Now if you only holiday in the UK, then go passenger side.