Branch office wireless - no guest network

Hello all,

We have an XG at our main site which is working well.  It has a normal, bridged user network and a guest wireless network on a separate zone..  This all works fine.

We deployed an AP at a branch office according to https://support.sophos.com/support/s/article/KB-000036475?language=en_US . The bridged network works fine, the guest network is visible and clients can connect, but when they do they do not receive in IP address. 

I have tried adding a 'fixed' IP address with the correct default gateway to the wireless connection, but cannot ping the head office network or even the gateway. 

I have looked at a Wireshark trace of the AP traffic and cannot see any obvious errors, but am not sure what I am looking for.

Any help would be appreaciated.

thanks

Adrian