When you say runs continuously do you mean the fan runs until you switch off the power or does the fan eventually stop too?
One last thing to check is the photocell. Give it a clean. It's located at the end of a thick black cable which is inserted into the blast tube or stuck/cliped on part of the control box (where all the electrics are handled).
You might, as previous posted stated, just have a problem with your control box and you could pick up one for your model and fit it quite easily. If it doesn't work bring it back straight away and get your money back - good thing to do is to tell the plumbers merchant it's a "Reillo YOUR MODEL" then if it doesn't work bring it back and say it was the wrong one and you need a "Reillo 7GB" which they won't have and you should get your money back.
Do you hear sparking? You can safely remove a burner and "fire" it on the ground (good ventilation required and have someone with your to power off the burner if it fires). You will see sparks from two thin metal bars in front of the nozzle. If not check wiring and move then slightly closer together 3 to 5 mm.