Thankyou Ralf

I haven't used the machine for 10 days since I have been so cross and
frustrated! I seem to remember that a very small bit of fluid is pumped
(hence streaking where this has splashed onto film and given more
development), it gives up the ghost and so pressing the start button to
override relay then gets the rest across.

The frustrating thing is that it hardly ever seems to happen when using
water in the chemical bottles to fault-find and with no film in the
tank. Lulling me into a false sense of security, it then recurs once I
am using E6 chemicals and film......

The fact that it is intermittent would indicate electrical fault of
some sort wouldn't it? If so and being unfamiliar with these Jobo
machines, where is the relay situated? I have found, but not yet
checked the other items. Will endeavour to do this later tonight.