Just been looking at 1.3 multijet diagrams on google (with my phone so cant go on details) and yes i can see what you mean there is 2 auxiliary belt. One seems V shaped and in a vertical position and other is horizontal with tensioners etc
The V shaped one is avalaible in different sizes depending if car has air conditioning or not so i presume that this one runs the ac pump and something else. Sorry if i cant be more specific in what the belts drive but i can get in much detail with my phone

Dont think I will get a chance to check it today,but any info is great,thanks turbo pip.I reckon the outer belt runs the power steering pump only and the inner one runs the altenator and water pump.Going to start a few more threads as I have found a few stupid things the previous owners mechanic did.