A minor thing that has bugged me is this;

Left Side;

You should be able to tap it back into the correct, central place.
Yours seems to be in good shape for a 2003. Is it the original? Others - like me! - have found that over time the rubber dries, cracks and crumbles and looks very tatty. See http://www.fullfatrr.com/forum/topic28563.html
I removed mine completely: http://www.fullfatrr.com/forum/topic25936.html
Good luck! It's "bébéchoon", ackcherly, with accents. 'Steve' to my chums.
20 years ownership of Solihull products, ALL GONE NOW, sniff!
Current motor: Suzuki S-Cross 4WD auto, 1.4 petrol. Oh so reliable! 7 years now and no problems. Oh, all right then, a leaking shocker replaced under guarantee.
Previous:
TD6 HSE L322 Auto FF
2.5 TDi 4-door Classic
Disco II
And my 1st Rangie: in 1995, a 2-door VM 2.5 diesel Classic
Not to mention the Lada Niva before those. (I said not to mention it!)

Mine was like that, tried tapping it with a block of wood to slide it along, never budged. Eventually cut off the excess with a junior hacksaw........very slowly and carefully.

Yes it's the original, I just don't know why it's not even. Land Rover I guess

I'll probably just leave it then, as irritating as it is, I can live with it. I worry that by trying to shift it back an inch, something bad will happen

I slid mine off totally so you may be able to shift with some gentle encouragement There is a difference between knowing your sh!t and knowing you're sh!t

2005 Registered 2006 MY 4.4 AJV8 Range Rover Vogue

You might be able to move it, or it could be stuck with some of the glass sealant that Land Rover use to bond the glass to the door frame.
I removed mine when I resprayed the top tailgate, a bit fiddly as I think the assembly line fit this to the glass before sealing the glass in place.
Mine too was like yours, to remove it I used a hot air gun to soften the rubber and knocked it out with a rubber mallet and a piece of dowel.
A good place for rust to start as well, the rubber seems to rub against the paint and slowly over time rubs through the paint and starts rusting.
I didn't replace or refit the rubber when I had finished the paint job, later models don't have the rubber as far as I am aware.

Steve. 1968 Series IIA Pastel Green, nearly there project

I removed mine completely a few weeks back. At 1st it would not move so I sprayed wd40 along it and left overnight. With a lump of wood and some firm taps it started to move ok. After a clean and polish I like it better with the trim gone, a clean modern look all for free. Less is definitely more in this case