Sven, one of the 4/4 Sport owners will come along soon to answer this question; however, I wonder if you need to reset the ECU. The Aero models do not like their batteries running flat and this usually throws up all manner of issues with the ECU - almost always requiring a 5-minute reset of the ECU (basically, you press the reset, leave the car for 5-minutes, push the reset switch (fuse) back into place and then start the car).
As for your question reference the jump-start - I would make sure the engine is running on the car that you are taking the feed from - attach the cables - leave it about a minute before trying to start the Morgan and then have the person rev the engine (lightly) on the 'feeder' car whilst you try to start the Morgan. I should say that I am not a mechanic but when I had an issue with one of my cars, this is what I was told to do and it worked (I did try it another time and I'd actually killed the battery - so it didn't work!; however, that seems unlikely in this case). Therefore, please take my advice as that of a layman, not an expert when it comes to jump starting a car!
