Spoke to Madison who
Spoke to Madison who confirmed that you can buy it as a separate part. confusingly their numbering system is slighty different, their part no is 1ZD 9812 and the carrier’s on their site at http://www.ultimatepursuits.co.uk/products/details.aspx?pRef=69109&vertical=1
you should be able to get your IBD to order it. they have 2 in stock.