Ive been having the same issue for the last couple of years, I think they get progressively worse too, my LED's are now flickering quite badly, and I've noticed that parts of the LED's are not illuminating... I've done the side lights, and the day light saver (if thats what its called)
So, i'm looking to buy some more, the side lights are 501, what are the other lights ? i can't remember for the life of me...
Thanks
Jordan
PS I emailed PartsULike and they don't stock the day light bulbs, only the side lights...