I dunno if it is a "non-servicable" part.
What if it clogs? If you can find it, you can remove it and test it.
It is a one-way valve. Some of them you can probe with a pen, some you can test by cleaning and then blowing one end and then the other. If you can't blow from either end, it is clogged.
You need to hear it from a Land Rover Horse. Anyone who is a Landy mechanic can chime in, lets answer it once and for all.
Secondly, I trust the Land Rover dealer as far as I can throw him/her.
Adam in the NYC summer
