Do all x5’s suffer with the rear bush problem causing the tyres to wear out rapidly on inner edges? 

Morning Jay Welcome

Simple answer YES

To try and get low HNV into the car the rubber is quite soft so has a life of about 60 to 80k miles. The main culprit is the rose bush which fails but it's failure is masked by the air suspension so early signs are missed until it's totally shot and ruining your tyres.

Fortunately the rear suspension is a DIY job that can be done on axle stands ( I have done 2 my 4.4 and the 4.6) I would advise as you are going to be in there getting a kit and changing the lot including the inner control arm bushes. My 4.6 I did in a Saturday with the help of one of my sons (younger and bendier) I made my own bush pulling tools but they are on ebay for about £30 so the total cost of DIY should be under £200, not including a 4 wheel alignment essential after any suspension work front or rear and of course new tyres. On tyres be careful if your X5 is running staggered wheels (wider rear) how worn are the fronts? better to change all 4 if possible, if only changing the rears then at least go with the same make as is coming off to try and preserve the rolling radius and protect the transfer case.

If you are able to DIY have a look at www.pelicaparts.com for How too's with pictures

Good Luck 

Dave