Matt is spot on.
A few years back i bought a 95 fully loaded softdash RRC 3.9 with 125,000 on the clock, 118,000 with one owner. It had a full service history including all receipts for the services. It had been a company directors car so it was Dealer serviced for the first 118k. I sat down one day and totted up what he had spent on servicing. Bear in mind the purchase price in 95 was around £30k. IIRC he had spent that again on servicing !!! These are not cheap to run. So while you are buying a Range Rover for second hand Fiesta money they are still Rolls Royce money to keep.
With the P38 diesel we always advised people to put away £1,500 for a new head which would inevitably go. With the L322 the air suspension is a couple of hundred per corner and the gearbox is prone to failure so Magictiny might not be totally off the mark with his reserve fund unless you're real good on the spanners. What I would say is that if you are anyway handy then to immediatly buy dignostics out of your reserve fund. If the RR starts to play up then it will pay for itself in no time.
THEEE most important thing if you ae buying is for it to have is FSH. Search for Matts post (just click the view all post by matt button in is public page) he put in a monster post together on buying one and the various problems with them. IIRC he even included the recall stuff to watch out for.
I would say personaly that unless you're doing big mileage that a well serviced high mile one is a better value buy than a low mileage one. If you're doing less than say 10k per year then a well maintained, fully recorded 100k+ car will be far better value than a 60k with patchy history. I found with my P38 that even though the service book was fully stamped and all but the last was dealer serviced it didn't come with the history. I should have known better but I really liked the car so bought it anyway. Turned out that was for a reason. It had blown the head, maybe even twice. No record of that, it wasn't until it did it again shortly after buying it that I found out. V.Expensive mistake. One I won't be making again. If its dealer stamped but doesn't have the history then its likely got something to hide.