Technical Starter Motor Help 2.4td!

[geordie chris]

Hi i have a problem with the starter motor. this morning when i went to start it the car wouldn't fire up but i could hear the motor turning (wurring noise lol). I did a quick check and on start up everything work's fuel pump etc. So i bump started the car and it fired up straight away. So is there anything i can try before buying a new starter motor.
Also could anyone give me the part number it's a 2.4 td hlx.
Thanks in advance.