Slip sliding away
Solve the problem once and for all. Put a manual transmission in the 280CE. It looks like you're in the U.K. and there are plenty of 4 speed 240D trannys and 280 5 speed trannys there. The conversion is modular and can be done in a day if you've got everything lined up.
You'll need a MB pedal assembly, tranny, shift linkage from under the car, shift knob mechanism from inside the car and a proper length driveshaft.
We've done several of these switches and are doing another relatively soon by putting a 5 speed in a 300 Turbo diesel. You won't believe the difference in control and power and you never, never have to think automatic again!!!