197 Not Starting!

So i've had a nightmare with my car recently not starting ... its been to the garage and had the stater motor changed and a few other bits yet I get it back and it fails to start 1-2days later. Any ideas on what could be causing this? Battery seems fine as everything works etc

I've seen common faults to be fuel pump or TDC sensor; has anyone else experienced this?
 
Have you had the codes read ?

Whats the issue with starting your having? Is it turning but not firing or not turning over?
 
If it's not firing then it could be the sensor at the bottom of the gear box housing...can't remember what it's called but some one will charm in...it shuts the fuel pump off
 
1. listen for fuel pump prime the fuel system before you start the car ie a buzzing sound from the rear

2. if theres no fault codes then this could easliy be the tdc sensor - easy/cheap fix