The car was fine for the first 4 months, then the gearbox started to bang.
Took it to the garage I normally use and was told this is a common fault due to a leak. There was a leak on the gearbox and it had lost about 2 liters of gear fluid. So, my mechanic found the were the top-up screw which is on top of the box just under the air-filter. He added 2 liters (no more than that at a time) of fluid and it was fine, but then 3-4 month later it started again. We came to the conclusion that the leak is not fixable, we don't know where it is, and to stop the problem altogether would be a new gearbox, or just keep topping it up every 3-4 months when required. So we did and it's lasted till now still going strong.
Just one thing; it's a little difficult to reach the top-up screw and hard to undo; fine for a man who likes to not be beaten, but for a woman, not practical unless you are a mechanic of sorts.