I tried the sprays too but they weren‘t really much help. I‘ve heard of people smearing on all sorts of things from vick to mustard etc but a) you need to consider what theye things will do to the wood and b), more important, what they do to the dog. Humphrey used to have a wooden root chewing block which was really good (until it got jammed underneath the pine secretary and he chewed the leg off trying to get it out!!
) , they‘re a bit pricy but last forever and used to keep him occupied for hours, I can certainly recommend them. The only alternative ofcourse is to leave him somewhere where he can‘t do much damage, Humphrey‘s chewy phase didn‘t last very long, so it‘s would onl have to be a temporary measure probably.
You could always change the decor to „shabby chic“ and tell everyone the bannister is supposed to look like that!