my polo will not start when the engine gets hot. it turns oveer but will not go the whole hogg!!!

ive had it in the garage and they have replaced - the fuel filter, the o2 sensor & the coolant sensors.

When it does start it will only go a short distance before it wants to cut out again,

When i did drive it to and from work (10mins max.) if i switched the engine off, and then try to start it about 5mins later it wouldnt budge. like i said it will turn over but thats it. HELP PLEASE!!!!