As Less. mentioned, Tremona Garage is the place to order underbonnet decals. Top quality stickers. This is the best picture i have of where to put all the decals.
Big half-moon decal belongs to strut tower on left side. Three warning decals, one on the brake fluid bottle, one on the fuse box cover and one on the intercooler (biggest of them). 'Check oil daily' decal on the cam belt cover, asbestos decal to the right on slam panel, one on the header tank and two big decals (warning brake system and ignition timing) on the intercooler.