hotfix did not work-help please won't start

Hi all, i have a 1997 p38 rr and when its been run for 30 mins or so and then you go back to it 10 mins or so it is a bugger to start, you have to wind it over for about 1 minute then it will start with a cloud of smoke(very embarassing), i have had an auto elec do the hotfix but that has not made any difference, its had new glow plugs and full service even pluged it in at rr and no errors except air con needs gassing. Can anyone help please? thanks in advance....