Thanks everyone for help. In an effort to save a few grey hairs I pulled the original donut out and it turns out to be the same as on a Jag X350, S-Type etc. The part number is GAG03-001. Link below for one on ebay $60-ish landed from UK as opposed to $100 for a local equivalent.
Photo of original
https://drive.google.com/open?id=0B8PnVPDNncBwTHBXdG9qRzZUYjA
eBay replacement from UK - same manufacturer same part #
http://www.ebay.com.au/itm/400991005703?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
I'll update fit when it arrives and confirm if it works. Hope this saves someone some time/effort in future.