Mk3 gti stalls then won't restart!

Hi,
I have a P reg 2.0 Mk3 Golf gti that has been causing me no end of trouble and any help would be greatly appreciated. I have an intermittent fault that can leave me stranded unable to restart the car. It normal starts from cold no problem but then, sometimes after 1 mile, sometimes after 40 miles the engine will cut out. I could be going at 70mph or whatever and it just dies! It also happens when stationary in traffic the engine will just cut out. The car sometimes restarts fine straight away but othertimes it turns over but won't catch. This can leave me stranded for anything from a couple of minutes to hours until it randomly starts. Leaving me pushing the car to the hard shoulder or sat red-faced and unpopular. http://www.vwaudiforum.co.uk/forum/images/smilies/zx11.gif I have had it linked up to diagnostic machines but it has not come back with any faults. It can also happen when I have turned the engine off after a journey. When I try and restart it will just turn and turn but won't catch. I have already worned out one starter motor because of this! Please help it has been getting progressively worse and have had enough!
Cheers, Alan

Does your fuel pump run when this happens? Had the same problem once and it ended up being a dry joint on the fuel pump relay.