There have been problems with the JATCO boxes in these and others cracking pistons...but the first thing I would do is disconnect the battery overnight and then try again, it may just need to re learn settings. Whats the mileage on yours?

Unfortunately as with most modern autos that are 'sealed for life' there is not an easy way to check the oil level, do you have any leaks underneath it? Get a garage or gearbox specialist to check the gearbox oil level as a first port of call I would say. If it needs topping up it is imperative that the correct fluid is used. An oil and filter change wouldnt hurt but if it is a mechanical problem internally it wont help of course.

Have you had any work done on the car recently?

Edited by countryroads on 07/01/2013 at 18:11

Gearbox now fixed.It turned out to be a failed solenoid(s) and we were able to order up the parts for about £100 and hand them over to our local garage who did the job for another £120. Car now running as it should, chuffed to bits! Thanks for your input.