PS: Have moved on and done other levels and joined the forum tonight as I just can't leave anything without a gold star (or even a green).
No dinner again!!!

It's not the official way, but this worked for meSpoiler - highlight to read wrote:
PICTURE 1:
First use Stinky to move the boulders along the white lines. Place Stinky at the white X.
Switch to Loof. Place the metal box on the green X.
Switch to Peegue. Push the boulder along the red line. Push the other boulder along the yellow line. You will need Stinky's help to do that. Place Stinky at the white X. Place Peegue at his starting position.
Switch to Loof. Place the metal box on the red X. Push the boulder along the purple line. You will need Stinky's help to do that. Place Stinky at the white X. Place Loof at his starting position.
Use Peegue and Stinky together to move the metal box along the light blue line.
Walk Stinky across the collapsible bridge.
PICTURE 2:
Use Stinky to push the boulders along the yellow and red lines (one at the time).
Place Stinky on the purple button. Place Loof on the blue button.
Switch to Peegue. Move the plasma box to the green X. Push the wooden box along the green line to the blue button (remember to move Loof out of the way). Push the righthand metal box to the light blue X.
Collect keys and bonus coins and exit.