A friend bought a September 2008 BMW 530d M Sport automatic from BMW franchised dealer Bavarian Garages in Belfast in May this year.

It has the optional sport automatic gearbox (including the shift paddles behind the steering wheel). Within the first two months, it became apparent that the gearbox could decide to change from second to first unexpectedly, when decelerating at junctions for example.

It was returned to Bavarian, who carried out a gearbox software reset, but still the problem persisted. So back again, about a month later, and they carried out a learning function reset - again, the problem persisted.

The car was returned a third time, they currently have had the car since last Monday 5 December, and have reset both systems again, say this has "not completely cured it" but that BMW would not allow any more extensive work to be carried out under warranty.

We've read up on internet forums, and get the impression the car may need a new 'mechatronic unit', which it seems BMW are unwilling to stump up for. He feels quite strongly that he would rather reject the car than accept it with the unpredictable jerky changes from second to first.

We both have driven a number of E60 automatics which did not display this characteristic. The sales manager will be phoning to talk with him tomorrow. What should he do? Many thanks in advance