How do you replace starter motor on zafira 54

the starter motor is placed at the back of the engine and is quite tricky to get to,there are two 13mm bolts holding it on.the bottom is quite easy to get out but the top bolt is a bolt with a extra thread on the end with another nut which holds the earth cable in place,you first have to remove the 13mm nut and earth cable and then get a deep 13mm socket and remove the bolt.then simply take out your old starter and replace new one then put top bolt in,put earth cable back on and then the nut told cable and bottom nut then its done!!! jope this helps.