help my polo keeps randomly not starting!
 

I have a 52 plate polo and for some bizarre reason it struggles to start. This may happen every other day but if i keep trying and pump the accelerator it generally starts. In the summer when it was hot it was doing it more often..... every time I take it to the garage it starts first time. Has anyone heard of this problem before? A bloke gave me a push to jump start it during the the summer and said it was a common prob with polo's but I can't remember what he said it was..... the garage have no idea either..... any advise would be most appreciated before I get stranded somewhere! :)