sorted
i tried plugging the nas into someone elses router and reconfigured it. same issue.
did another factory reset and it popped up! took it home, set it all back up again and now its back up and running.
No idea what caused the issue but thanks for all your help guys, particularly godsell4
port 20 is still apearing as blocked via canyouseeme so if anyone bumps into this thread with a similar issue, its not port 20 being blocked thats the problem
