Thanks for replies. MIL light glows steady with ignition on or cranking engine.Obtained secondhand ECU with matching part number.Fuel pump now behaves normally i.e. runs for a few seconds when ignition first switched on and then stops.Engine still won't start but I assume this is because immobiliser is built into ECU & is not coded to key.MIL light now flashes with ignition on but it will allow me to access fault codes (none to read).I assume this means a tow round to Renault dealer to recode immobiliser?