AEBS and Second Router - can't browse network

I have an AEBS (Gigabit version) connected to another Router (Netgear DGND3700). This, in turn, is connected to a cable modem. So the setup is:

Internet > Cable Modem > DGND3700 > AEBS

The Netgear router acts as the DHCP server to the network and the AEBS connects on one of the LAN ports. The AEBS is set up as Ethernet in the Internet Connection section in Bridge Mode.

If I connect to the AEBS either wired or wifi, I can see all other devices connected to the AEBS in Finder and if I click on any, I can browse shared folders and/or screen sharing. If I connect to the Netgear router I can see the devices in Finder but cannot connect to them. I suspect it's something to do with internal routing but I can't find a setting on either device where this may being blocked.

Anyone got any suggestions what I'm missing or what I might try ?

Thanks in advance.