There is a rear arch part in two peices, either full or lower part made by a guy in Wales. Geunine parts were used to make the replacements so the match in theory should be good.
Lewis from here made and makes them.
https://www.facebook.com/whiteland.rest ... s?fref=ufi
These were ebay items you could order I will see if I can dig out some more info Lewis at Whitelands Restoration made/makes them. I have the off side pair sat in my garage waiting to be used.
http://www.ebay.co.uk/itm/172503568073