Fitting rear wheel.

Guys I need a bit of advice. I've had my rear wheel off a few times and whilst its not been too easy I have been able to refit it. This time however I am about to kill the cat as for the life of me I cant get it to fit back on.

The rear caliper is really the issue. What are your trusted proven ways of doing it. The set up in the caliper is really strange as the pad keeps swing out.

I's appreciate your help.