Can browse SMB shares fine but not scan to library

Hi All, this issue seems to have got the better of me and I have no idea what else to try. My configuration is:

Storage on netgear NAS boxes
Database configured in advancedsettings.xml to be a MYSQL server (on a different machine)
X3 Windows machines running Jarvis 16.1 connecting in
Access to NAS based media configured as SMB

The problem is that although I can browse the SMB shares when I go to scan them to library nothing happens. I first suspected the Windows firewall on the MYSQL server so disabled this. This worked and I was then able to scan to library. I then went to turn the firewall on again and add an exception (I already had one for MYSQL which I proved worked scanning media from mapped drives). This is where the problem lies the Windows firewall does not log any dropped packets and using wireshark I can see that the clients are only connecting over 3306. However I can only scan to library when the firewall is off?! So I’m pretty confused, does anyone know what I need to add to the firewall in the MYSQL box so that I can scan to library again?

Thanks for any help!