DD-WRT separate LAN from WLAN on WRT160NL linksys router

So, I decided to flash my router with DD-WRT to get more control over its configuration.  The primary goal was to create an access point where DHCP addresses were only given out from the wireless interface and to isolate wireless clients from everything else on the LAN apart from the internet.

So I headed over to www.dd-wrt.com, searched the firmware database for the latest version for my router.  Carried out the upgrade and all is well, connect to the web interface and ready to start configuring.  I fished out a relevant article to assist:  

http://www.dd-wrt.com/wiki/index.php/Separate_LAN_and_WLAN

Carried out all the steps, and going well, I can get a wireless DHCP address... But wait, no internet access.  

I could get to the internet before I put the WLAN on its own bridge.  Hmmm, lots of talk of iptable settings for the firewall script on the forums.  After spending 5 hours, trying and retrying different settings I can across someone saying that the firmware suggested in the firmware database for your router isn't necessarily the latest or best.  I did a bit more digging and I found what seems to be the latest version on their own website:

ftp://ftp.dd-wrt.com/others/eko/BrainSlayer-V24-preSP2/2012/10-12-12-r20119-testing/linksys_wrt160nl/wrt160nl-firmware.bin

Upgraded my router to this version, carried out the same configuration I started out 5 hours earlier and BANG, all working as originally intended and as designed.  

I'm not getting those 5 hours back.  Really, why have a router database if it is going to give you a "bad" version.  Ahhhrrrrrr. Moral of the story - always double check what you are upgrading before you start.  

Now, while the links above were the correct ones for me, you need to make sure you take the time to find the correct ones for your own router. Fortunately, I could browse the ftp site in my internet explorer and find the correct one for my purposes.

Hope this saves somebody sometime in the future!!!