Renault Scenic 2003 1.9 Dci

Hi All
First post so here goes!
I have an intermitted electrical fault on my 2003 Renault Scenic 1.9DCI. it occasionally does not start when you turn the key from position 2 to start. Replaced the main and key battery. Rocked the car to and fro it top to free off the starter pinion and the car started. I’m thinking it’s the starter motor itself. But I had a similar problem with a Mercedes A Class which turned out to be the immobiliser ring on the keyswitch

Does anyone know if the ring is a common failure on the Scenic or is the starter on the road out, the car has covered 106K

Also it seems a little 'flat', little pull below 2500 rpm, MAF gone?

Thanks