Sideface:Problem solved - it was a password problem all along - changed my password (as above) and suddenly "it just works" ... 🙂
Ha, I just went through exactly the same issue setting up my ER4!
I only figured it out by digging into the pppoe0 logs and learning that the broadband password was different to the login, probably would have had it fixed in 5 mins if I had just asked @michaelmurfy...
Actually MM, it probably wouldn't be a bad idea to add a quick note to the guide about it.