Well I had the same problems as you until I cracked it, here are the spoilers in increasing order as usual
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×No, you dont want the Wobbas joining the fray
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×You need to leave only one WW which will not follow you up the corridor
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×Ok , did you notice that the toggle at the top of the corridor opens the yellow door ? (hint,hint,nudge,nudge)
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×You must place the WW to the west of you and attached to the yellow door when you enter the corridor ....