When my user returns from paypal the 'thankyou for registering message' is being pushed right down the screen by an almost random seeming collection of modules from various areas of my site.
Is there a way to point the return to a particular 'page' or even better menu item so I can setup the modules to display?
What version of DT Register are you using? This sounds like an issue that was found and dealt with a while back. If you have this issue with the latest release, submit a support ticket please.
You can not modify to send the return to another page or menu item. However with the latest release, you should not have any issue like this.