[Sid Squid]

I'm not sure there is a diagram with enough detail to assist you there.
Anyway, the rubber seals go either end of the throttle spindles with the recess facing outwards, the throttle butterflies have the side with the number on facing toward the engine, as are the screw heads, and as you will have noticed when you removed them, their ends were clenched using a very specific tool - don't try to reproduce this, you'll damage something, use some threadlock. If you look closely you'll see the butterfly edges are not square - this will show you which way round they fit, the number goes toward the top, (the diapragm chamber). In your picture you have the connecting rod fitted wrongly - it's at the bottom on the rear carb but at the top on the front one. The larger of the two return springs goes on the front carb, and the longer plain end goes on the inner side against the carb body on both. The plastic 'top hat' shaped pieces are sort of spring guides.

Hope this gets you started at least.