my head lamps are condensated (2004 roadsta) my local bmw breakers said that u cant buy the seal alone and that i need to buy a complete new head lamp......
New rear covers can be bought, which have the seals...
Left:
63 12 6 928 413
Right:
63 12 6 928 414
About £9 each, and about £2.50 for a new clip if you wanted.
My nearside front one has got a tad condensated again lately, only very slightly, but I think the seal is the issue, so will probably get a new rear cover (the seal at the inside edge can get crimped on fitting at the funny angle (doesn't sit right basically), and mine had it crimped when I bought it, and the seal is now kinda damaged and is probably a point of entry for water)