Same problem here on my 2003. I went to a local auto body shop and was told it would cost $100 per handle to repaint . I decided it would be best to buy all new handles and replace. You can get 4 new handles from rover connection for about $200 and easily do the install yourself if you take your time. Although I have not done the door panel removal on the RR yet I have done it on several other cars to know it is fairly simple if you use a good door panel removing tool - like a soft cat claw -and you take care to not overly pry the panels out that may damage the clips or the panel itself. The learning curve is quick - once you do one door the next three go much faster - the key here is patience and a soft touch.
1) Disconnect battery
2) Remove panel screws (hiding under trim)
3) Remove panel - unplug electrics
4) Remove vapor barrier, or peel back to expose inside handle
5) Remove and replace handles
6) Reassemble
Don't forget to disconnect the battery (and wait 5 minutes) before taking off the door panels and disconnecting the air bag sensors - if the battery is connected you will throw a code that can only be extinguished by the dealer. I will try to find a listing of the door clip placement and screws/bolts that hide under cover panels, or I will take some pics when swap out my handles sometime this next month. Once you know the location of all the hidden screws and clips it is a fairly easy but time consuming process.