How do I stop my y reg Scenic 1.6 cutting out?

I suffer from the car cutting out when slowing down and stopping for Roundabouts and Traffic lights, it then proves to be a bitch to re-start. I have had the TDC sensor out and cleaned it which seemed to reduce the problem for a couple of days. I have even changed all the coil packs in case there was an intermittent fault there. Today another twist -- the light for the automatic gearbox came on and went out when the car was restarted which ran rough for about 200 metres and then all back to normal. I have taken it to a Renault specialist who said the fault may have been a problem with the engine temerature sensor. £126 later still no change to the cutting out.
Any ideas or better still answers out there ???.