Small imperfections are not uncommon on new cars regardless of their price, so it is a matter of how persistent you are prepared to be to have it resolved. However, you're right that you should expect a new car such as an expensive Range Rover to be perfect. We would suggest asking the supplying dealer to make an adjustment as a gesture of goodwill, but they may not agree to do so free of charge. You have the option of taking this up with Land Rover UK but they may agree with the dealer that it is within tolerance. If you are prepared to pay for the work yourself a better option may be to take it to an independent Land Rover or exhaust fabrication specialist who can even up the appearance.