Chris 24, I think you have convinced me!

My X5 has side rear airbags in the rear doors and the curtain airbags. It also has child restraint points for all three rear seats (these are detailed in the Australian Manual supplement). There is no mention of any way to deactivate the side airbags, although it does so not to put a child seat in the front with the 'forward facing airbag'.

I guess the child seat should be in the centre?

Thanks for the insight!