Master 2.2 dci hot starting - help !

[viz]

Hi, i have a 2002 2.2 dci renault master. In the past couple of weeks i changed the fuel filter and found the clear fuel pipe has some air in it when left to stand for a few hours, not an issue apparently. A couple of days after changing the filter though it became really difficult to start once warm, ages cranking over before finally catching and now once warm thats it, it will not re-start. Its fine from cold and only a problem when re-starting. I am pretty sure its not the air as although its present i have bled it out from the top of the fuel filter on a couple of occasions and it does not seem to make any difference, still returns though. It also will not re-start if the fuel is still in the pipe and no air is present as it has not sat long enough for it to return.
My latest guess is that the tdc sensor is at fault and that the timing is just a coincidence.
The only problem is i cant find the sensor, can anyone help ?

[viz]

A quick update, it has now become more difficult to start from cold and wont start at all from hot. I got stranded after work the other day, it had sat all day and would not start when i went to go home. Lukily there were shops nearby so i got a can of easystart and it fired up straight away. Have'nt used it since as its a bit embarrasing having to take the van apart outside a customers house every time i want to go somewhere.
Does the fact it starts with easystart narrow down what could be wrong ? I am pretty much out of ideas now.