Ruphus:

 

This is generally not true. I used to design and build trusses for houses and avoided introducing load bearing walls to support trusses wherever possible. Load bearing walls require extra slab thickening or flooring design to account for the extra load. Also, the bottom chords (the horizontal timber that the ceiling battens fix to) are sized according to the design specs of the space. If we know the ceiling space was going to be used for storage, we'd increase the size of the bottom chord to account for the extra load.

 

The OP may need to get a copy of their house plans from the local council to see if there are any load bearing walls in the house.

 

Ok this is what I've heard. I've ordered the entire building documents from the council, but I'm not sophisticated enough to understand them unfortunately...maybe I need a structural engineer, but I can't imagine they're cheap.

I definitely know the attic was designed just to hold the roof though, not for storage.

Edit: and based on your description of load bearing walls, I highly doubt we have any.