Firewall/NAT

Morning,

I'm new to the M0n0 world, having previously been using Smoothwall Express and FreeSCO.
The plan is to configure the device as a filtering bridge, purely to use as a firewall for a VLAN segment. I have WAN, LAN and OPT1 interfaces working ok, WAN is connected to our internal network and the VLAN clients will be behind OPT1.
The issue I'm experiencing is that clients on the OPT1 interface cannot get an IP address assigned via DHCP. OPT1 is bridged to WAN, and if I assign a static IP then I can ping hosts etc on the WAN (our intranet) ok. I have unchecked 'Block private networks' and set up the firewall to allow all traffic on OPT1 (wan address is 172.16.0.17). It seems like DHCP requests are not getting through to our server.
My test client when given a static IP address can ping the DHCP server on the WAN, and the DHCP server can ping back the client. Running wireshark on the test client shows that broadcast traffic is reaching the client ok.
Can someone please assist me in getting this to work? Thanks!

unfortunately this is a known problem ,see this thread, with potential work arounds.

http://forum.m0n0.ch/index.php/topic,3430.0.html

Fix will be in 1.31 which we will see very soon (I hope!)

I have read though that thread and it makes sense. I've enabled the DHCP server on the LAN interface, and set to 'Only respond to reserved clients listed below' but still no joy. Could this be because OPT1 is bridged to WAN, so the hole is therefore not getting poked in the right place?