Volkswagen Polo starter motor, maybe

When it doesn't start does the engine turn over o.k ?

I'm not too sure what you mean. The engine doesn't turn over when it doesn't start. It makes all the noises it usually does, and the lights, wipers etc work but no engine movement. Sorry not mechanical at all!

No problem , your lights and wipers can work o.k as the power to operate them is minimal as to what's needed to turn over the engine .When you turn key to start car , is it trying to start i.e turning over , or does nothing happen ? If nothing happens it could be a flat battery or as you suggest , a faulty starter . Have you tried a jump start from another car when this happens , rather than a bump start ? If it starts ok doing this ,you should get someone to check battery cables / earths and starter connections .If all o.k , get battery tested . Any fast fit centre or decent accessory shop will do this foc.

It doesn't turn over at all and the engine doesn't struggle when its bumped started. I wondered if the starter was on its way out or would it just fail for good straight away? Thanks for your help so far!

Like all electrical parts they can just pack in. Sometimes the starter can have a bad spot or just fail.I would get battery tested first as that could be fault and that eliminates one possible cause .It's only a two min test , foc. Then if not that and all connections suggested earlier are ok , probably needing a replacement starter .Any auto electrician can check / test starter for you and probably supply and fit new part while you wait if needed.

I have same problem.I replaced a brand new starter motor. But new starter motor have worked only 3 days.The problem started again.I checked battery.It is very good condition.It clicks when I switch on ignition. I tried to get jump from another car. It has not worked.After 2-days later it works as normal.