The AAV is one of the items we seem to discuss frequently. There are at least 3 different part numbers, perhaps even more if one includes the pre-HE in the search.
Google some of the 3 Jaguar numbers in the thread provide above and you’ll find some vendors.
Be prepared for a shock – the part is ridiculously expensive.
Lots of info in the archives (the magnifying glass in the upper right corner of the window)