help with vaxhall astra 1300 dielsel?

I have a astra life estate will sart 99 times out of 100 but sometime will not start off key if you push it will start turn it staight off and it will start staight up,after so many starts it will not start again unless you push it off, the batties spins the engine fast all the time it is a astra 1300 diesel life any help please