Imobilisier issues R Reg Renualt Clio?

I have had many parts replaced by my local garage, and we have come to the conclusion that it must be the immobiliser. To start the car I have to hold down the clutch and lock and unlock the doors usin the fob.
I can drive the car with no issues for about two weeks then the car will lose power and chug then cut out. If I turn off the ignition and turn it back on again the engine starts again first time.
This will last about a week, various mileage before it conks out.. I have replaced the spark plugs , map sensor, ignition coil and air filter.. And a hose ( which was split ) anyone got any other ideas?
The car is a R reg, 1.2 petrol manual...

Charlie
February 2015