1.5 starter motor?

I am having starting problems at the moment and might need a new starter motor. Basically i turn the key and quite often nothing happens at all I tried taking everything apart and making sure all the connections were good and gave a liberal spraying with wd40, and this seemed to fix it for about a week, which makes me think its not the battery….

Anyway does anyone know what starter motors i can use on a manual 1.5 engine, i.e scirooco or mk2 ones? I cant really fork out for a new one cheers Johnny