Stoves 900GTF DO Ignition fault

(059043197 SN. 030356)

I was called to replace a flame failure device on this particular cooker, (I am gas safe registered). The customer then informed me that there was a problem with the ignition. It wouldn’t stop sparking. I’ve had this many times before. I first changed all the ht leads and checked for broken ignition plugs, they were all ok.
So I ordered a replacement spark generator. The original one was an open pcb based one.With N, L1,L2 & L3. The one sent was one of the newer types all encased in a plastic box. It had N,L1, L2, L3 mad L4. The outputs were re-ignition 1,2,3 & 4.
However, once i fitted the replacement, i wasn’t getting any spark at the upper oven. The input was at L3, but no spark there, so i moved it to the spare L4, but still no joy.
Either the ignition generator was faulty or i’m missing something. I have spent several hours trying to resolve this issue, but am hoping the unit is faulty.
Those bloody stoves cookers with the air pressure switch, having to put the casing back overtime, such a pain.
Does anyone have any tips in bypassing it?
There is a C,NC & NO.
Please help if you can, this is my first post on this site, someone told me how good it is. I hope so?
Thanks
Neil