Sophos Firewall blocking Web Browsers only!

Hello,

After months and months of waiting for Sophos to support Windows 8/8.1 with their Firewall I noticed yesterday that I could push it down onto my PC.  

After Sophos Firewall was installed I found that all web browsers on my PC (IE11, Firefox, Google and Safari) could not access any websites.  FTP, RDP, ping, VPN to Office File Shares, Email, Skype all still worked however.

I chose to do the obvious thing and temporarily disable Windows Firewall and Sophos Firewall (using "All all traffic") but still Web access via browsers woudl not work.  As soon as I uninstalled Sophos Firewall however - bang - Web access returned.

Can anyone point me in the right direction on what is going wrong?  Obviously I've not chosen to block outoging port 80 - and even if I had, why would it still be blocked when the "Allow all traffic" check box was enabled?

Web Control and Tamper Protection are both switched off.  AntiVirus on access scanning is on.  I can post up technical details if you wish  - but let me know what it is you want to look at.

Thanks,

Chris