VCDS lite and a suitable cable will let you find what the fault is and clear it, but unless its fixed as said above it will come back again. Most likely is a fault indicated with the drivers airbag, which would be the clockspring usually. VCDS lead can be found on ebay over here fairly cheaply, suggest you start with that. Read the fault codes and then look on here if your not sure what it means, something mentioing drivers igniter and intermittent is likely a clock spring issue. Given its the only part of the system that moves, and your dealing with a part potentially 21 years old, its likely going to be that. Might be lucky and find its something else thats not plugged in and can be fixed easily though, till you get the lead nothing more you can do about it.
I don't think a Haynes manual for the petrol Seat/VW models exists, even for the mk2 models. Most apart from the engine is the same anyway. I don't think the petrol Seats were particually common in the UK, most of the models would have been the diesel ones or the Ford petrols (which as your probabbly already aware are a completely different engine to the Seat/VW petrol ones). Was there something specific you wanted to know about? Fuseboard layouts are in the reference section here
