My wife has already
advised me that if hers kicks the bucket she wants another one..

She loves the X5. She said she wants the latest possible model like hers (she means an E53) with lowest miles because she loves her car and doesn't care for the new ones. Yes it's expensive to maintain, but we all say that because we mentally battle the Japanese gauntlet. As far as I am concerned Yes, we'd still had bought her X5 knowing what we know. (let's hope I don't jinx myself)
Here's my take on German vehicles:
If you want the exhilaration that you [can only] get from driving a BMW or Audi (we own both)
"you gotta pay, to play". Accept it or buy new every 4y/48k. Either way, you pay.