That can easily be achieved in a PA28 in 2.5 hours. Most aircraft used for the PPL navs would be cruising at around 105-120 knots.
Only five hours solo cross country are required for the PPL.
Tecman I'll get back to you on that with the references, meanwhile...
From what I understand anyone now with GFPT can just continue with training for the PPL, no need to go to RPL in between, just continue from where you are.
If someone is starting after September and they want to do the navigation component then why would they do the RPL syllabus?