I would like to connect to the my home network via vpn. This can be from anywhere. Looking at the vpn setup the big spanner in the works is that it needs the ip address from where you are connecting. Not much use then.
I verified this is the case by using my phone as a mobile hot spot and connecting my mac to that. Without the ip address of the phone you cannot connect.
Any ideas round this issue?

Which type of VPN are you using from your phone? PPTP...etc.

I have mine set up and working fine with PPTP dial in and it does not need the client (phone) IP to be set at the server end (home)?

Mine is on 2860, though the firmware is a bit different on the 2960, I cannot imagine that it will not be able to do a PPTP dial in from a mobile client. Maybe it's just a bit weird about the way it names the settings. Had a look in the 2960 manual but it's a little less help than it could be!

Yeh the manual is useless. Found a draytek online doc which didn't mention setting up an ip address but you had to to get it to work.

Fixed it. Basically ignore the manual and go the faq's on drayteks site and look at teleworker for 3900

Although I think you've found your answer already, Dial-In VPN accounts are configured through User Management on the Vigor 3900 and Vigor 2960 routers:
http://www.draytek.co.uk/support/guides/kb-teleworker-smartvpn-ssl-3900