Hi i,ve got a small problem with a Worcester heatslave 18/25. Control box is a dk 970 and its a bentone burner.The burner goes through all the proper sequences oil pressure is right and the burner fires for about 5 to 10 seconds then goes to lockout.It all points to the photocell but the old one was replaced and the problem is still there.Could it be a controlbox problem or a combustion problem as the nozzle and shroud were very dirty.The boiler was serviced by British gas in August so should be ok any feedback will be most welcome