If you want people to use other payment methods, in particular over PayPal, which is obviously the most popular and widely used for many reasons (not just on eBay), then you need to give them more reason to change their habits than PayPal give to maintain them. 

That is no easy task. 

PayPal is fast, convenient and offers protection for the payment, everything you offer to counter that disavails buyers of these advantages and frankly, not many buyers want to be asked to advantage the seller over advantaging themselves. Yes, you can say that registered post must be used if paying via PayPal, but many will interpret that not as a benefit to them if they use bank deposit, but a penalty for using PP. So not only do you need to give them a good reason for using other payment methods, it needs to be done in a way that doesn't leave a buyer questioning why you don't want them to have the benefits PayPal offers. 

The only way that has been done that I know of, is via reverse psychology, and it was a few years ago now - the climate here and use of PayPal has changed so I doubt it would have the same kind of effect. That is, to offer PayPal and bank deposit, then state PayPal Preferred. 

Historically and anecdotally, when people say Bank Deposit Preferred, payments via that method decrease. When people say PayPal preferred, payments via bank deposit increase (if but slightly).