Has Bosch written on it and a part numb: 008 545 66 32.

Posted on a UK forum too and just had the reply: "that part number is a MB number not a Bosch and is the 5 speed auto gearbox control unit".

If so though, wouldn't this be a common component of all our cars? Surprised the garage hadn't seen it before and haven't exactly been inundated with replies..... maybe it's something particular to my model (124.061). Where's the gearbox control unit normally located?