Hi there,
£53.50 all in for HEL stainless on EBay seems ok:
http://cgi.ebay.co.uk/Ducati-748-749...temZ8059407958 Goodridge, HEL, Earls, Woods, etc all are recognised brands.
Just make sure they know yours is an upside down rear caliper.
two other contacts:
http://www.inoxbolt.co.uk/productmainmenu.htm http://www.mandp.co.uk/home.aspx MandP also do their own budget range that I've found ok when the kitty was almost empty
Good luck - Frank