ISP upgrade - remote access broken - ipv6

[killunit]

Gi,
Since a recent uprade on my ISP to a 2GB fibre connection my ISP provided new router does not support ipv4 port forwarding.
I have been able to access Subsonic locally on both IPv4 & IPv6 addresses, but I cannot seem to get remote access working at all since the upgrade.
Hoping for some insight, help and guidance on how I might restore my remote access.

I typically use iSub client on iOS. This is where I want to restore access.
my IPv6 address works there locally when connected to my localnetwork on wifi or ethernet.

If there is some "client" solution with a relatively low cost I am willing to try that also but prefer just to use appropriate native network configuration settings / firewall settings or whatever is required to setup access securely to my home server from outside my local network.

Thanks for any help you can provide.
Jason