How do you take off headlight adjuster on a vauxhall corsa headlight?

Unfortunately there are 4 different Corsa models, Mk1 (called a Nova in the UK), Mk2, Mk3 and Mk4 (the current model).

Not only does each model have completely different headlamps, but each model had more than one type of headlamp fitted.

In each case the method to remove the adjuster is completely different.

This means that to answer this question more then 12 different sets of instructions would be needed.