Ok further checks with the owner revealed....
Problem occours hot or cold
Fuel pressure and injectors checked when it was at dealer ok
Fault codes read and cleared but no report as to what they where
New crank sensor fitted at dealer
More info gleaned just now,
The immobilisor ecu was checked as when the problem occours when the igntion key is turned the lights go out and the starter turns but if your slow turning the key the light comes back on and the starter stops so possible key and column ring issue, does the key need recoding?