Apologies for my first post being a cry for help, but i'm sure someone on here will be able to help me.

I've got a S2 RS Turbo that i'm having starting problems with. It's fine in the mornings, or when it's been left for a while, but if I go somewhere and leave the car for just a few minutes then try and start it again, it won't work for about 5 minutes (which can be quite annoying at the petrol garage). I've replaced the starter motor twice, which seemed to sort the problem for a week or 2, but after that the problem was back again. Any ideas?