Good morning, Rachel
The smell (which, incidentally, is completely harmless) is caused by the oxidisation of the linseed oil within the printing inks.
On coated paper, the ink sits on top of the paper coating and cures (oxidises) comparatively quickly because it is naturally exposed to the air. However, on uncoated paper (which is what Toast use for their brochures), some of the ink penetrates into the body of the paper, so is less exposed to the air. The ink curing process on uncoated papers therefore takes longer, hence the smell of the linseed oil oxidising lingers longer.
Long may you continue enjoying Toast's beautiful brochures!