"Another thing mentioned in the kodak sheet is that this c-41b process requires no washing, is this true for jobo use, surely the chemicals will contaminate each other if not used one-shot. "

Jobo recommends a 3-minute rinse (6 changes of water) after the bleach and 5 minutes (6 changes of water) after the fixer.

Kodak does not recommend a rinse after the bleach and only a 3 minute rinse after the fixer. I've been fiollowing Jobo's recommendations without any problem.