Thanks Stevie,
You are correct, the mapping was fine. Turns out I missed the assist setting for un assisted start. Selected un assisted start and hey presto, the clutch paddle works fine - too good really, out of three "new" starts, two jump starts and resulting penalty....... The manual clutch really increases the immersion level. Love it!
The clutch paddle is the 3 DRAP paddle assembly (https://www.3drap.it/product/universal-magnetic-clutch-for-custom-steering-wheels/) and I use the Leo Bodner BU0836A 12-Bit Joystick Controller. I intend to add two rotary switches to the wheel, the will also work through the LB board. The board fits neatly inside the top of the wheel.