Maybe so Eddie - I would of thought with it being sealey based and most models had a fan - but if they did do a turbo model then yeah it might of not had a fan - I would put one in it .The contactor coil should be energised by a switching component on the PCB, when the torch trigger is pressed. Depending on the coil voltage, this may be an electronic component ( a transistor or a TRIAC ), or a small relay. There should be a label on the contactor coil showing the operating voltage ( as opposed to the voltage & current rating of the contacts.... ).
It would also be useful to know the voltage specification of the gas solenoid coil; it should be getting power at the same time as the contactor coil.
You can bypass the torch trigger switch by unplugging the torch and replacing it with a simple wire jumper inserted into the two small sockets that accept the torch cable pins on the Eurotorch socket.
If the auxiliary ( standby ) transformer is providing power to the PCB but the contactor still does not pull in when the trigger is pressed, the fault is likely to be on the PCB. If you post photos of both sides of the board it may be possible to suggest where to check next.
Not sure about the fan. There is certainly a round fan-sized grille in the back of the cabinet. You could check for mounting holes and unused spare wires. Maybe it is only fitted to the SGA175 Turbo model.