cut out twice this morning? 500 sec

Just had a replacement fuel pump fitted so im guessing its not that. Im gunna retry the terminals again, also as the car is being started on LPG as the fuel guage is showing empty (might be an obvious one buut I reckon the guage may be at fault as I put £15 in and it didnt budge) so next thing would be to add £20 fresh fuel as the stuff in there now might be very old.
Also maybe fuel lines? Fuel pump relay??? Anything else Im missing?...


