The sprag is just a fancy bearing. Last time I replaced one I took the sprag to a bearings supplier, they matched it from their reference sources and it cost £35 - the identical item. Ducati does not manufacture its sprags, it buys them from a bearings supplier, just as you can.
As well,as making sure your battery is well topped up before starting, it's probably a good idea to replace your starting circuit cables with fresh, beefier ones, as lively, healthy starting makes for a healthy sprag clutch. I used an expensive kit from the U.S. for this but others reckon cheap cables from Halfords work just fine.
Take the original with you, try any of these: 1 Local Bearings Stockists in South East London | iLondon Bearing Stockists - 020 http://www.yell.com/ucs/UcsSearchAc...&location=South+London&scrambleSeed=490500214
