Windows 7 and VPN. Newbie Help needed

[Rincewindwiz]

Newbie problem here trying to set up an VPN.

Current test setup is

Win7A ->Wifi -> BT FON router-> internet-> my router -> Win7B
IE reports the public IP address of Win7A as 188.222.xxx.xxx (it was previously behind the same router as Win7B)
IE reports the public IP address of Win7B as 188.222.xxx.xxx

I have created the server VPN on Win7B (All network components except IPv6)
my router has the VPN port assigned to the correct PC (192.168.y.yyy)
and Win7B Network Connections) reports 1 client connected
It also reports the user I logged in under as connected.

I have created the client VPN on Win7A and Network and sharing centre reports it connected to VPN (Work network)

All of this sounds good except now what?! I am expecting to map a network drive to the relevant share on Win7B and away I go but I seem to be unable to map a drive to a shared folder.
I know Win7 has shared folders because I can access them from another PC connected to the Win7B network.
I've stopped both firewalls but that makes no difference

So how do I set up this share?
Why can I not see any shares when I type in the IP address (192.168.1.66) to the start box or explorer
When I try 'browse' in map a network drive - it sits there for a long time and then gives me the local drive shares. and nothing under the Network heading
Network diagnostics report network seems setup correctly but Win7B is not responding

Baffled - as usual with MS issues!!
All help gratefully received