Door-to-Door Royal Junk Mail opt-out

I am cross, partly at myself. It seems that many of the pizza companies, supermarkets, charities depositing plastic bags, and the like through my letterbox in defiance of the "No junk mail, no free newspapers" sticker were not employing annoying casual deliverers but were instead using the Royal Mail, whose employees are under strict orders to ignore such signs. They have an opt-out procedure, which is somewhat tedious. Basically, you email them, they email you a form, you print it, sign it, send it back. After two years, they start sending you junk again without giving you a reminder.

I'd like to know if they'll respect forms sent in by people that haven't sent emails requesting forms explicitly. I've put the form here, if you'd be willing to try this and let me know if it works! (it's Freepost)

The email you're certifying that you've read and understood is the tedious:( Small print )

I'd also be interested if anyone has any ideas how to make this process more streamlined. Ideally the sort of enter-your-address-and-click-OK thing that the MPS has would be nice.