The only thing to remember here is. As you wait, all the models get older.
What I mean by this is, the entry price to something like an L322 will continue to drop. And ones currently considered newer, will in time also become older.
Saving up more money will obviously allow you a larger choice when buying. And if you have a pot of cash put aside for repairs, then great. But the reality is, this won't change or affect how durable or reliable a vehicle will be. And you could easily pay, £10, 15 or 20k on a Range Rover and end up with more problems than a £6k one. But that's true of almost any marque.
And don't early L322's uses the same power systems and electrical systems as BMW's (forget if it's E38 7 Series or E39 5 Series). Either way, BMW sold a shed load of both. But the newest of those BMW's are 2001 and 2003. The point I'm making here is. People manage to buy and own these BMW's without drama. And without having to spend huge on them or a massive initial outlay. Looking at Autotrader, the 7 Series go from under £1000 to the most expensive ones at about £5k.
A BMW isn't a Range Rover. But that doesn't mean a Range Rover costs massively more to maintain.