Been doing some digging on this....there are quite a few signals between the autobox and ECU....one of which might be a temp signal (there is certainly RPM and retard - ground this signal if converting to manual) plus a couple of others.

Need to get the old AVO on the signals and monitor them during warm up to see what they do.

By the way, mine does NOT hold first when cold......

Sometimes mine delays 1st to 2nd change (until 25mph) if Im moving off on even a slight uphill - thats quite annoying too. Garage told me its responding to the accelerator sensor movement.

Thank fcuk both my cars are manual... I'll decide if I want to do 6000 RPM in first or 800 RPM in 6th thanks 

On my 2.6 FBW, I can by-pass this feature by easing-off the pedal slightly just when the transmission seems insisting on not shifting-up, then pressing the accelerator again slowly and the box shifts-up as soon as I re-apply the pressure on the pedal even at low rpm.

This works for all gears and it is how I drive the car until it warms up. The 'downside' is that the this rsults in car being driven very mildly and you can't drive the car hard if using this technique, but then again you probably wouldn’t want to drive it hard anyway with a cold engine...

I did not try this on my previous 2.5, so I don't know if this possible only on the FBW or will it work also with the old-style throttle engines - can someone check?