I've just been on the Dow Corning website and found this tucked away in a Q&A pdf
Dow Corning® Silicone Sealants Frequently Asked Questions
Q: Will cured silicone sealants yellow?
Most do not yellow. Some oxime sealants, which contain amines, will yellow and should not be used in places...
Hello,
I've just refitted my bathroom and 3 weeks ago I applied some clear Dow Corning 785 silicone around my new bath overflow and basin taps. After only 3 weeks it's turned a yellow/brown colour.
I thought Dow Corning was supposed to be one of the better brands so it was really a post...