Diff Breathers - Where to they terminate under the bonnet?

This may help. From www.discovery2.co.uk

www.discovery2.co.uk Breathers

Overkill IMHO.
If you get to the level of the current breathers you already have many more serious problems, like the transmission ECU being submerged and probably the BCU and probably floating away.

Regards Philip A

You may have missed the point. The 2nd paragraph in the link preamble explains where the factory breathers are fitted, which is the answer to the question asked. I agree with you, the mod is a bit over the top, but some like to go the extra yard, for whatever reason.