yeah it must be a SEAT loom then, the one in my garage and the one on my mates abf swap are MK3 looms with lighting seperate from engine.
its not a massive deal though, just open it out and strip the bits you dont need. My fusebox faq will help you id the plugs, but you can just start at the ecu plug and pretty much bin everything that isnt connected to it.
try to ID as m,any of the plugs as you can before you stary, and as you're unwrapping the loom put a bit of tape round it every 30cm or so, to hold it all in roughly the right shape.